How to properly calculate the right quantity of chemical products used in a process?

Question

We are modelling a water treatment plant, where are used several different chemical products.

We are having some problems defining the right value to represent the consumption of some products, like the polyaluminium chloride, that is used in a solution at 10% in our case but the ecoinvent record is not clear whether the product is pure or is already a solution in some percentage.

We use this voice: polyaluminium chloride production | polyaluminium chloride | Cutoff, S, we are not using the "market" voice because we know the exact trip done to deliver the product.

Can someone help me understand? Thank you

Answer 1

You should check the unit process, then this becomes more clear, or also, as the documentation that comes with the dataset in openLCA shows, the ecoinvent background report. From the system process ("S"), the specific modeling is of course not visible any more.

It is a good decision not to use the market process (as you say / do), in case you know the transport for your case.

Comments

Thank you for the answer, I checked the unit process and saw that there are different kind of water involved  (some used for cooling) and is not easy to do a mass bilance between inputs and outputs.
From the description I can't understand if the product made by the process is to be considered "pure" or in a sort of solution.
It would be helpfull if someone more experienced can help me how to consider this PAC in my case.

I use PAC in a 10% solution in my WWTP, do I have to do a proportion or is it right to address the PAC present in ecoinvent DB 1:1 with the PAC used in my Plant?

Thank you

---

You can also look in the ecoinvent documentation or check the ecoinvent unit process online. There you will find additional information that clarifies whether the output flow includes the water or is the active ingredient only.