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I'm modelling LCA of polypropylene using Ecoinvent 3.9 cut-off. The idea is to compare the effect of landfill and recycling. The recycling should be open looped so it is used for a different product. However, the idea would be to see how much recycling would lower the impact in gradle-to-grave analysis.

I added "waste plastic, mixture" as avoided product in inputs but didn't have any affect on the impact results. Where I should add the waste to see the impact with and without recycling?
in openLCA by (140 points)

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by (6.9k points)
Hello Tilda,

When modelling with a cut-off approach, you get very little benefit from open-loop recycling. As far as im aware, it is not allowed to include displaced material from recycling your product at EoL, as that will be double counting with cut-off system boundary.

However, it is of course still possible to model this, to show the systematic benefits. (Usually consequential is used for this).

To model this in cut-off i recommend an EoL process that includes the collection, cleaning, shredding, and re extrusion into granulate. Then the displaced product is granular PP, with a degree of recycled plastic, determined by the market within the geographical scope you are assessing.

The competing product would have an EoL process that includes collection, and landfilling.

If you only investigate CO2, be aware that landfilling is very low intensity.

Good luck with your modelling.
by (6.9k points)
Hello Tilda,

I can recommend the consequential modelling approach. This is slightly more complicated and time consuming, but will likely give a more recognizable result.

Cut-off approach can also show what you want, you just have to be aware of your inputs and outputs.

This was a little vague, and i apologize. I am sure you can find more resources online on how to model with cut-off or consequential. If not there is the classic LCA "Manual" by Hauschild, Rosenbaum and Irving.

Good luck