Waste modelling help please.

Question

Hi OpenLCA forum. Do you have any example or tutorial on how to model waste. For example, I have modeled the production process of a reinforced concrete structure already. As I want to study the whole life cycle of my project, I would like to include the disposal part.

For instance, I want to allocate 42% of steel waste to recycling and the other 58% on waste treatment. At the same time, the 30% of concrete waste is recycled and the remaining 70 % is going to land fill. I cannot find a good documentation on waste modelling from your manual. I want to make sure that I am doing the correct modelling procedure in Open LCA. I am in need of urgent help. Thanks very much in advance.

Answer 1

Hi, that is a good question. So far, you need to model waste treatment as a service; we follow here some existing databases like ecoinvent (and I agree this is not too intuitve at first).
Best wishes,
Andreas

Comments

Could you please elaborate more on treat waste as a service? I am using Ecoinvent waste processes as outputs and allocated them physically based on he percentage that I mentioned, but I am unsure of the results of my calculation.

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In a nutshell, waste treatment is modeled so that the waste treatment process delivers a service (treatment of waste xy) to the process which is creating the waste, and since the "real" flow should be an output flow (waste is going from the waste production to the waste treatment process) the sign of the waste treatment service (on the input side of the waste production process) is set to negative to maintain the mass balance.
Hope this helps!

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Does that mean I have to model all the waste treatment processes in the input along with the source of the waste? And then one output reference flow? How about the allocation method in which I have to separate the wastes by materials from the source?

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Please check if I am doing the right modelling

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Hi,
"Does that mean I have to model all the waste treatment processes in the input"

not really - if you check any ecoinvent waste treatment process, there this principle that I tried to describe is already applied. For your own processes, if a process is creating waste, and this waste goes to another process for treatment, the waste treatment process, then you should model it so that the waste treatment process delivers a service (treatment of 1kg waste) to the process where the waste is created, and in this process, the waste treatment service is input. You should change the sign to preserve the mass balance; the process producing waste thus has input of -1kg waste treatment service (for example), which is provided by the waste treatment process.
Hth,
Andreas

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Andreas,

I too am having this problem.

Is there nay way you could provide a step by step guide to doing this?
Not all of us are as familiar with the software and terminology as you are.

Thanks.