Recycling Loop

Question

I have a recycling process loop in my system. In my filter unit, I produce 100 kg of process liquid, and 80% of it is reused in the system in an upstream mixer unit with feedstock and fresh water. The remaining 20% of the process liquid goes to waste. However, this closed loop is creating an issue, making my calculation process lengthy for LCA to converge. How can I model this loop? Kindly help.

Answer 1

Hi Swarna Saha,
there are different ways to model recycling in openLCA. One using a loop is described in the manual (https://greendelta.github.io/openLCA2-manual/allocation.html?highlight=recycling#allocation-for-recycling). However, if this results in problems with your operating system, you can also just decrease the amount of overall freshwater used and add the respective feedstock in the process where you produce the process liquid. Additionally, you can directly receive 20 kg of wastewater in the output. This allows you to not model the loop.

Hope this helps