Page 17 - Plastics News May 2020

Single-use plastic bags and their alternatives Recommendations from Life Cycle Assessments
Summary from all studies (by different environmental impact categories
environmental impacts are greater. Reusable and the impacts in the end-of-life phase, and always reduces
degradable alternatives, such as cotton or paper bags, the use of raw materials for producing new bags.
should be considered as options to reduce these
impacts. The collection and sorting systems need to be able to
effectively segregate degradable plastic bags from non-
In countries where incineration is prevalent as a waste- degradable bags, and use corresponding processing and
treatment approach (with or without energy recovery), recycling technologies for effective treatment.
paper, cotton, and other bio-based bags with no fossil
co-polymers have the advantage of climate-neutral In countries where sanitary landfills are a prevalent
incineration. They might have a lower total impact on approach for waste disposal, landfill gas should be
the climate compared to conventional SUPDs, collected to reduce impacts to the climate. This also
particularly when the materials are produced with reduces the climate impacts of degradable bags (e.g.,
renewable process energy and the bags are sufficiently paper and cotton).
reused.
Systems to prevent conventional plastics (fossil and bio-
Bio-based bags do not guarantee a lower environmental based) from entering the biological waste treatment
impact. To achieve a lower impact, they need to be
stream need to be in place, as conventional plastics can:
reused, which requires a reusable design and also (1) clog treatment processes, and (2) end up on/in soil as
incentives and consumer awareness for reuse. Also, part of the compost (conventional plastics do not
biomass production (forestry and agriculture) needs to degrade in biological processes and leave residues
be sustainably operated and low-emission energy has to behind). For example, the bio-degradable bags used for
be used in the production processes. The use of fossil-
collection biological waste should look distinctly
based co-polymers in bio-based plastic bags needs to be different from non-degradable plastic bags.
reduced or avoided. If they are compostable, segregated
organic waste collection should be in place and waste
Recommendations on what to consider when using
bags sent to composting.
LCAs for decision making on shopping bags:
Consumption and user behaviour
Re-use of all types of bags needs to be promoted, as this The results of LCAs depend on the specific choices made
in the study regarding, for example, system boundaries
extends the lifetime of bags and reduces impacts from
the production of new bags as well as the waste and input data. A transparent LCA report includes
management. Durable bags, such as higher quality information on the important methodological choices.
However, it can be difficult for a non-LCA expert to
plastic bags and cotton bags, have greater
environmental impacts in the production stage; understand the reasons for making these choices and to
assess the relevance of the system boundaries etc. It is
however, if consumers use them a sufficient number of
times, a shift to durable bags can bring significant recommended that LCA experts are involved in
environmental benefits. interpreting results. They will be able to clarify what
kind of knowledge can be gained from the given LCA and
Incentives and education need to be provided to why another LCA can generate different results.
consumers to reduce their consumption of bags.
Alternatives (such as reusable bags), clear consumer A one-on-one comparison of bags with different sizes is
information, sensitization and communication need to not accurate, because consumers might need a larger
be in place for consumers to reduce or avoid the use of number of bags if they are smaller. On the other hand,
single-use bags. the functionality of the bags is also not accurately
reflected by their capacity, because a small bag is often
Campaigns and educational programmes need to be a sufficient substitute for a larger bag. The most
provided to students and citizens to minimize the accurate comparison is somewhere between the two.
littering of bags (especially plastic bags), as well as
other impactful behaviours such as dumping and open The LCA should include country-specific data,
burning of plastic bags. particularly on the waste-management system, the
weight of the bags and the number of times each bag is
Management of end-of-life bags used, because these factors vary between countries and
Recycling of bags in state-of-the-art facilities reduces have an important impact on the LCA results.

MAY 2020 17 Plastics News