How to look at waste treatment with ecoinvent

Question

I want to look at the Impact of waste treatment and I have numbers on how many kg of wood, plastic, paper, etc. is disposed of. I am creating a process using the Opposite Direction Approach but am unsure where to put the input and output (waste flows or reference flows) and where to use a negative sign. I’m sending a screenshot as well. Looking forward to your help!

Answer 1

In the opposite direction approach, you must use product flows not waste flows (unless you are using a really old openLCA version). Then, simply set a negative sign for waste input (the process that has in reality waste output), and for waste output (the process that treats the waste) a negative sign as well. Hth, and I would rather recommend the waste flow modeling ;)

Best wishes,

Andreas

Comments

I see!

So I have the reference waste flow that I created manually  on the input side, which is the sum of the mass of all waste disposed by the company.

On the output side I have waste flows for each category of waste and their respective mass with the according provider.

Is that correct?