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Re: [greenyes] The big picture on glass
This glass discussion seems to have touched a few nerves.  The emails
have been flying fast on this listserv.

I do have a couple of things to add though.  The first concerns the
energy costs of using glass vs. recycling glass.  The answer is that
there is very little net energy savings from recycling glass.  It takes
almost as much energy to melt glass cullet as it does to melt sand and
the other raw material components of glass.  Cullet glass does melt at a
slightly lower temperature, so there are some savings in the manufacture
itself, but if you add in the cost of collecting and processing the
glass curbside and getting it ready to go to the glass plant, the
savings are not that great.  Of course it takes more energy to make an
aluminum can from raw materials, but at least in bottle bill states
where cans are recycled at fairly high levels, aluminum comes out a
little better.  In non-bottle-bill states, aluminum is probably worse
because of the high energy cost of making new aluminum as opposed to
recycling old aluminum.

Glass only comes out as a clear energy winner when glass bottles are
washed and refilled many times.  Plastic PET bottles can also be washed
and refilled, with good energy savings, although nobody is doing so in
the US.

As far as Pat Franklin's comment that glass is the most benign material
in the waste stream, this is true for glass that is going to disposal,
but it clearly isn't true for glass that is littered.  Broken beer
bottles on the roadside are no fun, and broken glass in paper is much
more of a problem than other beverage containers in paper, since the
other containers are relatively easy to separate out.

Metropolitan Portland, and pretty much the state of Oregon as a whole,
is moving to keep glass out of paper in the curbside programs.  Glass is
usually collected separately.  It does keep our paper much cleaner, and
our residue levels in Oregon are much lower than the levels at MRFs in
other states.  However, a recent study conducted by Metro shows that we
do still have problems with nonrecyclables that end up in the paper
bales at the mills.

Peter Spendelow
Oregon Department of Environmental Quality


---------------------------------------------
Date: Fri, 11 Apr 2003 14:09:46 -0700
To: Andy Telfer <cwma@no.address>
From: Sharon_Gates@no.address
Cc: greenyes@no.address
Subject: Re: [greenyes] The big picture on glass
Message-ID:
<OFF18F3309.7505B7AB-ON88256D05.0072B4E6@no.address>

--=_alternative 0074404A88256D05_=
Content-Type: text/plain; charset="us-ascii"

There is a piece of the "big picture" that nobody has mentioned in this 
recent discussion of glass:  energy costs/savings.  While I don't have 
percentages handy of the energy used to produce virgin glass vs recycled

glass, it is my understanding that the difference is substantial.  The 
issue is not "to recycle glass, or not to recycle glass."  The issue is 
how to recycle glass in such a way that it doesn't contaminate other 
materials in the recycling stream.  I have heard of places that have 
single-stream-except-glass collection and have drop-off locations for 
glass.  This sounds difficult, but possibly worth the effort.  Does
anyone 
have experience with keeping glass out of their otherwise-mixed 
collection, but still including glass in their program?

Sharon Gates
Recycling Specialist
City of Long Beach, California
562/570-4694






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