Waste flow emission

Question

Hi everyone, I'm struggling to evaluate waste emissions. Basically, I have a whole supply chain for which I know all the inputs and outputs, and then I need to evaluate only the different waste flows for this whole processes. Example: I am in the agricultural phase of pears (growing + harvesting), some of these pears will go to be sold, some other are not good so they will go to biogas production, biomass production, animal feed and more other. So, I want to do evaluate the emissions of the "not good" production that are not going to get sold. As I got, it can be considered as avoided products, so they won't increase the emissions of my whole process, but what I need is to evaluate them, not as an avoided product. Also I don't know how to assign to this the end-of-life product reference as biogas, biomass etc. . I'm using ecoinvent database. Thank you everyone.

Answer 1

Hi, interesting question. Probably avoided product does not fit since there is not easily another process creating "rotten pears" - you could go for biomass or so but it is a bit a stretch.

If you consider the "not good" pears a byproduct, you can apply allocation, e.g. via price. However, then, you cannot perform an LCA about using this product directly (so, turning them into biogas), since biogas is of course a next product. What you can do is making an assessment of biogas from rotten pears, using allocation in the pear harvesting / production step which is part of this product system since the not good pears are in the supply chain of the biogas. Hopefully you understand what I mean? All the best, Andreas

Comments

Thank you for the reply. I am Not very sure if I got it, and it actually looks like something I was also trying to do. I will try to explain it practically, however I don't know if my approach is the same as yours or if it can work.
What I was thinking to do is basically to replace in the ecoinvent process " biogas production from grass | biogas, from grass | Cutoff, U " the grass input with my output from the pear supply chain. I know that it will be very approximative given that all the input of this process are for grass, but this is the best I got.
Could it work or is a too big assumption?