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Re: [greenyes] The environmental impacts of recycling glass
Bob Kirby provided us with some interesting and useful info on the use
of recovered glass as a sand substitute in compost:

"The cwc did projects using glass both as a hydroponic growth medium
and 
combined with compost to make topsoil.  In both cases the glass (16
mesh and 
finer) was basically the same as sand.  Maybe slightly alkaline."

Since crushed/pulverized, recovered glass works as well as sand in
manufactured soils it seems the only downside is the cost.  (And that's
a biggie!)  As you pointed out, picking up relatively small amounts of
glass in 40 ton diesel trucks doesn't cut the mustard.  Add processing
it at the MRF and the added value increases more.  That method of
supplying sand obviously adds far too much value to warrant serious
consideration as a feedstock by the compost operators and manufactured
soil producers.  No doubt the sand mining industry uses some pretty
energy intensive equipment too.  I guess we can conclude that the sand
mining industry is able to move sand to the glass makers much more
cheaply simply because of sheer volume and throughput.  (i.e. lower
cost/ton)  When you consider the small fraction of glass hauled on a
refuse truck and processed by a MRF vs. the large amount extracted and
hauled by sand mining, this becomes obvious.

If that will always be the case, then deposit systems that relieve
local governments of the financial burden of adding value to recovered
glass or landfilling the glass is the only remaining alternative.  But,
at only $50/ton (2.5 cents/lb) to bury it, it's quite a bargain, no?

Someone recently posted a very salient quote from the November/December
2002 issue of the Brooklyn Rail.  It bears repeating.

"Capitalist growth and profitability depend as much on the destruction
of wealth as on the production of it.  while salvaging the value
contained in a discarded but perfectly usable desk is rational from an
environmental and social point of view, it is irrational and not useful
for the furniture industry, which must produce and sell more and more
desks in order to thrive.  Ulimately, the environmental crisis, of which
garbage is just a subset, is inseparable from the logic of our whole
economic system."





B. Wayne Turner
City of Winston-Salem
Utilities Division
phone: (336) 727 8418
email: waynet@no.address

"Experience is what allows us to recognize repeated mistakes."





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