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[greenyes] Glass and rocks
If the choice in the community is between glass disposed or glass collected to be used for aggregate, then I believe it is still worthwhile collecting glass.   However, I think Bob and I would fall in the same camp that one should do everything to get glass into a higher resource market.  That said...

1.  Recycled aggregate has resource value and reduces environmental impacts.
There is a higher value to glass (or rocks) recycled as aggregate rather than disposed, but aggregate does have some material value and reduces environmental impacts.  Turning glass into aggregate through screening and crushing would not be inordinate handling for the material value gained, especially when one accounts for both energy and environmental impacts of virgin aggregate.  

Transportation is a major cost of virgin production and one that is increasing quickly as siting new quarries in urban areas (at least this is the Oregon experience)  becomes increasing difficult.
 
2.  When you have recycling collection for one-third of total discards, the incremental collection cost to add glass is small.

3.  The processing system and cost to produce a glass aggregate is different and less costly and extensive than the processing system needed to produce container or fiberglass quality material, which must have carbon and ceramic contaminants removed, as well as some color sorting for many markets.  Aggregate does need some level or carbon/organic control, but much less than for containers or fiberglass.  Ceramics and color control are no problem.

This level of processing at the MRF (screen and crush) to produce aggregate is comparable to the cost of the digging, screening, crushing, transportation cost to market, and eventual environmental remediation associated with virgin aggregate production.  
 
4.  Collecting glass is an important platform for future market development.  Even if your only initial glass market is aggregate, it provides the future opportunity to develop these other niche markets, such as tiles, sandblasting media, and other, which you have done such a great job documenting with the Clean Washington Center reports.  


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