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Re: [greenyes] Single Stream - Reply to Follow on Questions
Food waste collection is being done in several cities.
Portland is looking at adding it within the next few years.


>>> "Wayne Turner" <WAYNET@no.address> 04/11/03 01:31PM >>>
Peter Anderson posted:

"Since glass is such a large fraction of the container weight, we'd
suffer a
significant overall loss of recovery were we to JUST drop glass, and
need to make that up somewhere else in most cases.  For example, would
residential mixed paper be added or, if it already has been, what else
that be.  That needs to be determined first in order to assess how
single stream MRFs can sort that out.

But, the bottom line answer tends to be yes.  Without glass, we have a
potential pathway to not suffer from single stream's debilitating
In Greensboro, NC where we run a single-stream, fully automated
recycling program using the large rollout carts, the broken glass is an
issue.  When I worked there (still live there) I estimated our glass
breakage to be 50% at least.  As Peter pointed out, mixed broken on a
MRF sort line is impossible to sort out into colors for traditional
glass-to-glass recycling.  And the markets for mixed broken stink. 
Peter also rightly points out that glass, by weight, makes up a large
fraction of what's in recycling containers on the curb.  But it also
makes up a lrage fraction by weight of residue from single stream
programs.  With residue management costs tied to the tip fee at the
local landfill, the presence of large amounts of glass in the residue
stream increases these costs.  Higher residue costs = lower net revenues
for the MRF operator and the program operator.  In addition, the lower
commodity prices for ONP and other fibers with mixed glass contamination
further erodes revenues.  

On the positive side, I'd much rather take a hit on the overall
reduction numbers than on the efficiencies and costs.  Speaking as a
program operator, removing glass from a single-stream prorgram would
make life much easier and our costs lower.  But from a political
perspective, I'd probably be martyred for suggesting such a move.  In a
manner of speaking, we've done this to ourselves by looking only at
reduction goals and how best to achieve them without regard to the
environmental impact of the materials.  Take C & D for example.  I could
easily begin posting increased waste reduction numbers here in
Winston-Salem by propsoing and implementing a C & D recycling program. 
But in the grand scheme of things, how much environmental impact does C
& D debris have as opposed to the MSW soup?  Plus, since C & D is buried
in our unlined facility, diverting it would not have the beneficial
impact of extending the life of our lined facility.  Since glass doesn't
take up much room, I doubt seriously if it's direct inclusion with the
garbage would greatly reduce the life of the landfill.  Half of its
going there anyway as residue.

I'd much rather boast a program that considered the known envirnmental
impacts of materials and diverted those most likely to cause
environmental damage than those that may be heavy yet inert, like glass,
yet yield great reduction numbers.  And I wouldn't feel the need to make
up the loss of recovered glass if added materials didn't yield known
environmental benefits.

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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