Study no 3
In study no 3, composting, anaerobic digestion and recycling of PLA are compared. Two types of recycling are
considered, i.e. feedstock recycling and chemical recycling. When PLA undergoes feedstock recycling (case
3[PLA1]), it is mainly recovered in blast furnaces where it used as a reducing agent or processed into methanol.
This type of recycling thus does not allow the production of secondary plastics products. However it is still
considered as a type of recycling since it is a form of material recovery since it leads to the production of
methanol. For the part that is used in blast furnaces, it can be discussed whether this end-of-life option should be
classified as recycling since it is a form of energy recovery. However, it is not only the energy content of the
material that is used but also its ability to reduce iron oxides. It has thus been decided to consider this alternative
as a form of recycling. However, to avoid confusion, this scenario is differentiated from the other scenarios in the
results tables.
In the case of chemical recycling, PLA waste goes though a hydrolysis process and is then repolymerised as PLA.
Chemical recycling (case 3[PLA2]) appears as the preferable option for all the indicators assessed thanks to
savings in virgin PLA polymer demand and thanks to a low energy consumption for the recycling process.
Anaerobic digestion also performs better than composting because some electricity is generated with the
obtained biogas and replaces grid electricity. The feedstock recycling scenario has performances similar to the
anaerobic digestion scenario, except for energy demand where feedstock recycling is more beneficial.
Study no 4
In study no 4, incineration without energy recovery is compared with composting and landfill for Multibio
multilayer film. Case [MUB1] corresponds to a degradation rate for the carbon content of 30% for composting
and landfill while case [MUB2] corresponds to a degradation rate for the carbon content of 50%. The only
indicator in this study is climate change and the results show that composting is the most beneficial alternative
whereas landfill is the worst option. This is due to the methane emissions occurring when the material is disposed
of in landfills. Incineration has little impact since the incineration of biobased materials is assumed to be neutral
regarding climate change (taking into account that the CO 2 content of the PLA-based biopolymer is mainly based
on biogenic CO 2 ).
Study no 5
Study no 5 assesses the performances of recycling, landfill and incineration with energy recovery regarding
climate change and energy demand for PLA. Once again, recycling appears as the best option. Landfill performs
better than incineration for climate change, although some energy is recovered from incineration. This may be
due to the fact that it is assumed that PLA does not degrade in landfill, thus reducing the impacts from the
process. This assumption is justified by the quotation of two recent studies of the same author.
Study no 6
In study no 6, composting and incineration with energy recovery are compared for PLA and cellulose. The
materials satisfy the biodegradability and compostability requirements of EN 13432. For climate change,
incineration appears as a better option thanks to the production of electricity and steam, which replaces energy
produced from natural gas and oil, which corresponds to the Danish electricity mix mainly based on fossil
resources. However, for the other indicators included in the study, i.e. acidification, photochemical oxidation and
toxicity, composting performs better for both materials.
Study no 7
This LCA looks at the complete end-of-life of different types of plastics and bioplastics packaging. For bioplastics,
this study compares incineration with energy recovery, composting, anaerobic digestion and feedstock recycling
for a packaging made of maize starch. In the feedstock recycling scenario, the maize starch packaging is used as
a reducing agent in blast furnaces.
Regarding climate change, anaerobic digestion and incineration appear as the best alternatives thanks to the
recovery of the energy produced. On the contrary, composting is the least preferable because of emissions due to
the CO 2 and CH 4 emissions accompanying the biopolymer degradation. Composting is also the end-of-life option
with the highest energy consumption. This can be explained by the absence of energy recovery. Incineration with
energy recovery is the preferable option regarding energy demand.