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Hello,

I'm doing a LCA on a process that produces marketable products from a waste material. As database, I'm using Ecoinvent Cut-off allocation for modelling the raw materials. This allocation, doesn't take into the benefits from waste or recycled material.

But in my LCA simulation, and in some stages of my process, by-products are recovered and could have a positif impact on the environmental impact categories (such as water recovery lowers the water footprint). Therefore, I was wondering if I could add these valuable by-products in my LCA simulation as avoided product to create a positif impact, even if this is not consistent with the cut-off allocation method of Ecoinvent used in the upstream for the raw material ? Is this not recommended ?

Thank you for your help.
in LCA Collaboration Server by (120 points)

1 Answer

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by (69.4k points)
Hi and welcome,

indeed, the background database should be consistent with the foreground modeling, especially if it contributes to the final results with a rather high share.

Also, btw., you should not model your foreground system in one process but rather in several ones, as you also say there are several stages. This is typically more clear and also easier to maintain.

In this foreground model, you can of course add credits for by products, that are given to recycling (unless this is rather waste and not a product).

To make your model more consistent, you could switch to the APOS system model then in ecoinvent.

Best wishes,

Andreas
by (120 points)
Hello Andreas and thank your for your reply.

When you say
"In this foreground model, you can of course add credits for by products, that are given to recycling (unless this is rather waste and not a product)"

I don't understand, because this is precisely what I cannot do if my backhround database uses CUT-OFF allocation ?
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