How to account for rinsing water?

Question

Hello,

I'm trying to take into account waste. Now, in my process, the products are rinced first and later washed with detergents. How can I take this into account within OpenLCA?

Do I add the amount of water as an input and the same amount as output? Or do I add the amount of water as an input and the same amount but with a negative sign as output? Or do I just the amount of water as an input and that's it? Or do I need to do something else entirely? None of the water and detergents react or are lost.

Thanks in advance for your answer,

Eline

Answer 1

Different "strategies" are possible here, I would model the input, rinsing water as input product (e.g. tap water), and the output as waste water (and waste flow), which then goes to a waste water treatment plant. The "double negative" ( - - ) approach works too for output water but is typically unintuitive and error-prone. Best wishes, Andreas

Comments

Dear Andreas,

Thank you very much for your answer! How can I do this then for detergents? Or things like paper to store products in between production steps? Are there flows for waste detergents and waste paper?

Greeting,
Eline

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Also, this double negative approach, does this mean that you put the value negative in the input AND negative into the output?