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[greenyes] pulverizing is not recycling glass
it is not recycling to use pulverized glass as an aggregate/drainrock at construction sites or anywhere else...it's re-use because the glass is still in it's orginal form, just smaller, and it's composition has not been changed/amended.    some of glass re-use (instead of recycling) comparative energy savings comes from 1) the avoided expenditure of energy in the extraction of gravel/limestone/sand and 2) the avoided disposal costs of glass landfilling and 3) the streamlined labor/transportation issue of using gravel transporation equipment and staff services for moving glass instead of the gravel.    any thoughts/data available on that?  :}melissa terry just a thought. 

Helen Spiegelman <hspie@no.address> wrote:Thanks to John Reindl for supplying yet another piece of credible testimony 
underscoring the limited environmental benefits of recycling glass.

Everyone needs to understand that the environmental benefits quantified 
below apply only when the glass is recycled back into glass. The much more 
common practice is to "recycle" glass into drainrock/aggregate substitute 
at construction sites. This "recycling" application represents a complete 
write-off of all the energy used to transform the sand into glass in the 
first place.

Is glass recycling a benefit to the environment or a feel-good exercise at 
considerable public expense?

Helen.

At 09:05 AM 04/14/2003 -0500, Reindl, John wrote:
>Hi all ~
>
>I have seen various computer models that tally up the environmental impacts
>of recycling glass. The latest -- and very clearly stated -- is in the 2001
>edition of "Integrated Solid Waste Management: A Life Cycle Inventory", by
>Forbes McDougall, et. al.
>
>On pages 441-442, Table 22.3 compares about 50 parameters, and I would be
>glad to copy and either mail or fax the tables to people.
>
>Here are some of the data, expressed on a metric ton basis of finished
>product:
>
> Parameter Virgin Recycled
>
>Engery (GJoules) 14.5 11.04
>
>Carbon dioxide 145,600 57,000
>
>NOx 1500 2880
>
>Suspended solids - water 7760 796
>
>Chlorides -water 99,900 8,410
>
>Total organics - water 68.5 80.7
>
>On the energy issue, a gigajoule is a billion joules and there are 1054
>joules in a BTU. Thus, making a metric ton of glass from recycled material
>saves about 3.3 million BTUs, or 3 million BTUs per US ton, according to
>this source. In comparison, according to data in the March/April 1981 issue
>of BioCycle, an article by Jerry Powell puts the savings at 2.95 million
>BTUs a ton, although the article has alternative estimates of 1.3 to 2.5
>million BTUs. In the same article, it is noted that a gallon of gasoline has
>128,000 BTUs.
>
>The data do not include the impacts of collection, processing or
>transportation, which is included in other sections of the book.
>
>Other LCA models also exist, including one by Argonne National Labs, which
>looked at the distance to which cullet can be transported before the energy
>of transportation exceeds the energy savings. If I can find the data of
>these other studies, I will let people know.
>
>It should be noted that on a per ton basis, the energy savings from glass
>are less than the savings from all other products listed in the above book.
>The book listed above does not evaluate the relative importance of the
>various environmental impacts nor does it look at a possible economic value
>for the individual impacts, as is done in environmental valuation studies.
>
>John Reindl, Recycling Manager
>Dane County, WI
>
>
>
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