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I've been reading many answers in this forum and none seems to actually answer the users' questions or just partially.

I don't know where actual LCA practitioners get their information from, I've been in several courses and the explanations about recycling modeling and burden allocation are horrible.

I do realize that combining questions is not an option in most forums but the issue is complex and will require some.

1. Modeling recycling using waste flows:

Example: i use 100% recycled scrap steel in my product, i can recycle 100% of the scrap steel at the end of life of the product.

Problem: There is no predefined steel production process using 100% recycled steel in ecoinvent.

Solution i would like to choose: Closed loop approximation, basically using the concept of "avoided product"

Question 1.1: why can i not just use "avoided product" on a waste flow and choose the steel flow used in "steel production process"?

Question 1.2: do i have to wrap the waste flow into a product flow?

Question 1.3: Or should i use, "waste avoided" in the steel production instead, choosing scrap steel as the avoided waste? (i assume i should not do both otherwise it is double counting)

Question 1.4: I constantly hear that i should never create loops in my supply chain. so i should not use a waste output directly as an input flow. why is "avoided product" so different?

2. APOS, Cutoff, Consequential:

I generally understand the concept of all of them. But it seems like absolutely no one actually knows how to use APOS databases and just vaguely says "they are complex so i only do cutoff".

In APOS recycled aluminium can potentially have a larger impact than the same can in Cutoff... I kind of get it but no one actually explains in DETAIL why, and how to avoid those issues when using APOS.
Maybe it is a problem of the LCA sector and is currently treated more as a subjective art rather than clear science... and I'm okay with that i just need a clear answer as to why everyone is so vague about this

3. It would be great to use this thread as an archive for the most complete waste, recycling, circular modeling,... - books, videos, tutorials, and other learning material. So please drop the info on how you learned about it here

in openLCA by (190 points)
by (190 points)
since noone seems to be able to answer i will document my learning here

Webinar by Swedish Life Cycle Center on problems of modeling recycling comparing different options:
https://www.youtube.com/watch?v=vLDckoETMg0&ab_channel=LifeCycleCenter

Sums up the issues and different results and differences in outcomes when using different methods

Seems so far like there is no consensus on what is the best method to use
Simple cutoff or circular footprint formular after PEF seems like the best choice.. is what i got from the webinar

1 Answer

0 votes
by (250 points)
Thank you very much for posting this, I have the same problems and after weeks of trying out, learning, watching videos, I am getting realls frustrated
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