softwood production vs waste emissions

Question

I am trying to do an assessment on the production, transport to customer and disposal of wooden home appliance covers and would need some feedback on the market for wood waste emissions which seem extremely inflated.

Results:
In my Results, production and transport makes up just a view percent but wood disposal (the wood waste process) makes up around 90% of all emissions... that doesnt seem right

Production:
I am using the ecoinvent market for sawnwood, board, dried 20% which includes production, then i add a sawing process (for sorming the board into the right shape, adding waste and sawdust outputs etc)

Disposal:
For disposal i am using the waste flow " market for waste wood, post consumer U" (EcoSpold 2 intermediate exchange) 
I am very surprised by the massive emissions that i get from this waste wood flow so i am wondering if i did something very very wrong in my setup.

Then when i use the waste flow "market for waste wood, untreated U" the emissions drop to like 5% of the emissions when calculated with "market for waste wood, post consumer U"

I dont know where the issue is

Thanks in advance for your advice!

Answer 1

Hello Berndk,

1: Please explain a little more. What kind of system boundary are you using? (Cutoff, Consequential, APOS, etc.)
2: What LCIA method are you using? One with an uptake of biogenic carbon (-1/+1 method) or with no uptake of biogenic (0 method)
3: From what i see, the "market for waste wood, post consumer" is not a waste treatment process, but a product flow process. Is this the one used?
4: Are you only looking at GWP or other impact categories as well?

If you answer these questions i might be able to give you a qualified answer. Before, its very difficult to know where a possible issue may arise.

Comments

Apologies for the unclear question

1.
I did use the APOS system which i still need to fully understand (basically the problem in APOS is that becuase of the processes included in a recycled aluminium soda-can for example... a virgin aluminium-soda can might end up having less impact than the recycled option)
I did read the article on this topic here:
https://pre-sustainability.com/articles/finding-your-way-in-allocation-methods-multifunctional-processes-recycling/

2. I was using ImpactWorld+ Midpoint since im interested in normalizing and summing different aspects into human health and ecosystem quality impacts

3. here the actual definition of market for waste wood:
This is a market activity, representing a treatment mix. In the case of products needing treatment, market mixes are supplied by the activities treating the product in the geography defined by the market, and they supply the activities needing to treat the product, as they have generated it as a by-product in the Undefined processes (present as a negative input in system models). Transport to the treating facility or losses are also accounted in this type of markets, when relevant.;This is the market for  'waste wood, post-consumer', in the geography of Europe.;Transport from producers to consumers of this product in the geography covered by the market is included. The activity starts with the input from the treatment processes. From cradle, i.e. including all upstream activities. A market for a material for treatment (wastes or recyclables) ends with the provision of treatment, i.e. a mix of treatment providers, to activities that generate the reference product as a waste/by-product. Dataset documentation: https://v391.ecoquery.ecoinvent.org/Details/LCI/a5db93b1-f379-45f2-b1ff-fa44ea8ecc80/290c1f85-4cc4-4fa1-b0c8-2cb7f4276dce

I am using the waste flow: "waste wood, post consumer" (provider: market for waste wood)

4. I just used GWP as an example. I looked at all impact categories and in the majority of them the waste wood flow makes up 90% of the impact


I now used Cutoff system boundaries and redid everything. Now i am getting a much more realistic oucome.

i still need to fully undersant APOS and whether it is in any way beneficial... for now it seems everyone is using Cutoff to controll system boundaries better.

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Hello again Berndk,
Yes, i would also recommend using a version of cut-off, or using consequential and system expansion. It is much simpler to explain what you see when using either method.
I am happy that choosing a different method yielded more realistic results. APOS can be a wild beast.
Good luck on your modelling.

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thank you! super helpful!
is there any good reading material on how to propperly model waste systems in APOS or consequential with system expansion? it seems like a lot of people just say "im going with cutoff becuase apos is super complex"

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I would be interested in good reading material as well. It is horrible, there are no goo examples.