Interesting question. I would think that the model might differentiate between waste that can be recycled and waste that cannot. Same thing for waste from nonrenewable resources and waste from renewable resources. My last thought would be the model needs to have its output developed in the context of the project type from which it is generated. Buildings typically create more waste than highways for instance.

Thanks for the answer, Douglas D. Gransberg

My current work involves the development of this model in the CDWM.

The wastes like chippings from blocks I use the to backfill trenches, and improving on the road.