The commingled waste facility that process our project waste work as follows: They weight the container once it arrives from job site, then separate the diffents matrials into percentage of the load volume. After that, they run the numbers into volume to weight ratio formula and comparison between material relative the actual load of waste. Their formula was develloped by a registered engineer, specialized in waste processing and treatement. For example, a container rolls in, waste content weight, say, 5t. 50% of this volume is steel, and the other 50% is mineral wool. They then run the formula and the result is, say, 4.9t of steel and 0.1t of wool. A detailled report specific to that load (and specific to the project) is then produced showing those numbers, and how the diverted products are recycled by their parteners. Would that method be acceptable for multiple material streams (in this case steel and mineral wool = 2 streams) , and project specific diversion rates?
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Nathan Gauthier
Director of FM Integration and SustainabilityShawmut Design and Construction
22 thumbs up
May 5, 2017 - 12:26 pm
I'm not the expert, but I see two potential issues:
Calculations can be by weight or volume but must be consistent throughout.
* Seems like this could be overcome as you're being consistent w/in the dumpster. If you have true volumes of the separate materials you could just report everything in volume, no reason to use weight at all.
Visual inspection is not an acceptable method of evaluation for documenting this percentage.
* This seems to be more of a sticking point. How are they getting the specific volumes? If it is just estimating based on size of pile that sounds like visual inspection. Your example is a bit easier with only 2 materials, but what about in a commingled dumpster with the typical mix of 4, 5, 10, etc. materials to be separated?
There is also the question of what is supposed to be allowed vs. what the reviewers would accept. Reviewers have been accepting visual inspections for years even though they're not supposed to. You could most likely get this accepted as it is better than what they typically accept.
RETIRED
LEEDuser Expert
623 thumbs up
May 8, 2017 - 1:27 pm
Nathan - Thanks for stepping in with your detailed response.
I would note that most of my teams want to use weight instead of volume because it is usually more advantageous if there is a lot of heavy materials like concrete/block/brick or steel. I agree that having a true volume is needed.
You have brought up good points regarding how this volume is being determined. It does seem like it is visual inspection instead of actual volume measurement. (One of my clients uses various sized containers to measure the volume of commingled materials after they have been separated.)
William - I would say that your measurement system is fairly robust as compared to some that I've heard of - especially since you have involved a registered engineer to help define the system. If you can confirm more about the how the volume is measured, that would help you build a better case to capture the two streams.