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Input from Manufacturing Phase to Operational Phase

Posted: 13 May 2016 13:59
by Mara
Hi openLCa community!

I am currently working on an LCI for a membrane bioreactor (MBR)-based waste water treatment technology. I want to include the manufacturing of the single components of the MBR as well as the operational phase and the disposal of the single components. I am wondering now how to scale the manufacturing and disposal processes according to my functional unit which is 1m^3 of treated waste water. Because it does not make sense to allocate all the emissions etc. from buliding the MBR to an output of 1m^3 of tretated waste water, right? The same problem occurs with the disposal process..
I guess i will have to calculate something with the life span of the components in relation to the overall output of the MBR, so here is what I thought of: (with examplatory data)

The Manufacturing of a water tank needs 100 kWh. The water tank has a life span of 10 years if the MBR runs 365 days/year. The MBR produces 200m^3 of treated water/day, i.e. 73,000m^3/yr and 730,000m^3/10yrs.
In order to normalize the input of the manufacturing process to the FU: 100kWh/ 730,000m^3. Like this, 0.0001369kWh of the manufacturing of the water tank would be used as an input to the process producing the FU of 1m^3.
Does that make sense?

And, the follow-up question: How do I connect these two processes meaningfully on openLCA? Should I do it like shown in the attached screen shot? I.e. connect to Manufacturing with the Buffering (Operational) process via the flow "Water Tank"? Or should I have the calculated 0.0001369kWh as an input?

Thanks in advance!

Re: Input from Manufacturing Phase to Operational Phase

Posted: 13 May 2016 15:39
by aciroth
Hi Mara,
1) openLCA performs the calculation of a system, and during the calculation the outputs of a process are scaled to the input, thus you do not need to do this on your own. It is not incorrect as you do it (provided the calculation is correct which I didn't check), but you will receive the same result when you set up the water tank process so that it produces 1 entire tank. The input in the fertilizer mixer needs to be the realistic amount of water tank per output of the mixer, 1m³, so quite a small number.
2) the linkage seems correct.

Re: Input from Manufacturing Phase to Operational Phase

Posted: 17 May 2016 09:45
by Mara
Thank you very much, Andreas!