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[GreenYes] Re: Growing Global Interest in Food Waste Disposers

Per Anne's comment/request, at you will find six
contemporary studies - beginning with the UWisconsin study ('98) which Carol
Diggelman conducted (later published in "Waste Management and Research") and
ending with last year's report (exec summary) on the "Sink Your Waste"
initiative in Herefordshire/Worcestershire County cited in the WSJ article -
along with some commentaries. The study from Sydney also independently
assessed four options for food scrap management. Additional studies and
commentaries are available from me, upon request, as is a comprehensive
document summarizing findings - by topic, to make it easy to find particular
answers - from seventeen (17) studies, for those who really want to dive
into this topic.

Might be worth noting that in the U.S. food waste disposers daily divert
millions of tons of food scraps from solid waste collection, transport and
disposal systems. Probably fair to say that even in the Bay Area that
disposers daily divert a significant amount of residential food scraps - and
have done so for decades. After all, not much difference between food and
human waste - both @ 70% water, with similar chemical composition. Plenty
of studies of impacts/benefits re wastewater treatment systems, but there's
also substantial evidence in the form of the 'wisdom of crowds' of nearly
all municipalities in the U.S. having chosen to allow disposers for decades.
Dave Biddle's Philadelphia is one such example, where commercial disposers
have been encouraged for @ 15 years, in part to reduce odors and vermin
caused by food waste stored in dumpsters.

But the point of the WSJ article is that where disposers are not common for
historical reasons, and pressure is growing to find effective answers, that
municipalities are now making informed judgments/decisions about how best to
manage food scraps, with some choosing to trade investment in/reliance upon
wastewater treatment plants and biosolids processing for truck-based
collection and the challenge/cost of siting/operating composting facilities.
The article didn't mention it, but that's essentially the analysis that led
NYC in 1997 - after a decade of study - to fully permit residential
disposers (previously legal only in newer areas), and is now in the midst of
studying the efficacy of commercial disposers for the same purpose, albeit
with a new imperative: of reducing GHG emissions from whatever system is
pursued, vs. continuing to ship 5,000 TPD of residential and commercial food
waste to distant landfills.

As to Dan's concern about sewer overflows, that issue exists with or without
disposers; the added flow from disposers is less than 1% per daily household
water consumption/generation. In mass balance terms, using NYC as an
example, its WWTPs daily handle @ 1.3 billion gpd; if ALL 3 million homes
had and used a disposer, the added flow would be perhaps 5 million gpd, or a
de minimis impact - in the words of NYC's study.

Kendall Christiansen


From: Anne Peters [mailto:annep@no.address]
Sent: Thursday, February 28, 2008 6:52 PM
To: David Biddle
Cc: Dan Knapp; Kendall Christiansen; GreenYes@no.address
Subject: Re: [GreenYes] Re: Growing Global Interest in Food Waste Disposers

Good dialogue.
Note that the WSJ article, which I read, was not a glib endorsement but
really just a descriptive report of what's happening in Malmo, Sweden - and
a few other European cities. The garbage disposall was invented in the US
and heavily marketed here wth the post-WW2 housing boom - 50% mkt
penetration now. It never had much mkt in Europe but now is being
positioned as a green strategy there as limits of successful backyard
composting are being reached in places like Germany that have done it for a
while. The article reports on a study by Carol Diggelman in '98 looking at 5
different ways of managing food waste, and concluded that disposals that fed
to water treatment plants w/ CH4-to-energy recovery had a more benign
enviro. footprint than trucking food waste to LFs or even to compost
fcilities. anyone have a copy of tha study? Would love to see the discussion
in that.

David Biddle wrote:

Kendall-I would love a copy of the WSJ article.

Dan- It seems to me that the problems that biosolid systems are having in
this country are more a function of a dilapidated or under-sized
infrastructure and that this issue calls forth the need to seriously examine
that infrastructure. Also, in your climate backyard composting is probably a
bit more doable than in northern climates like Philadelphia, Boston,
Chicago, etc. In addition, in many cities people don't have space,
literally. Here in Philly the majority of backyards are postage size.
Finally, in studies I've seen, while the residential food waste component is
high, the commercial and institutional fraction is much higher. Short of
daily collection of roll-out carts, what is a Hilton Hotel supposed to do
with their 2,000+ pounds of food scrap and sauces?

I'm advocating (and Kendall and I have talked about this often) for a very
careful and thorough analysis of all the options for really solving this
problem, especially for the commercial sectors. If it means that cities need
to look at renovating with $200 million bond options or privatizing their
sewer systems, or whatever, then so be it. Certainly, if the Bay Area is
struggling the way you say it is, this process must already be underway. I
would hope all the Waste-Heads their are looking to be a part of the

David Biddle, Executive Director
<> <>
Greater Philadelphia Commercial Recycling Council
P.O. Box 4037
Philadelphia, PA 19118

215-247-3090 (desk)
215-432-8225 (cell)

on 2/28/08 4:16 PM, Dan Knapp at dr.ore@no.address wrote:

I believe that sewage treatment plants in the San Francisco Bay Area would
not be enthusiastic about the WSJ's glib endorsement of garbage disposals to
reduce solid waste. I have read several articles in the local press about
how these plants are so maxed out that they are sometimes forced to dump
untreated sewage into streams that drain to the Bay. In late January one
major sewage release in Marin County amounting to millions of gallons was
one of the lead stories on the evening news for a couple of weeks.
Following that spill, lots of dead shorebirds were found in the area,
although no conclusive link was established. Also, sewage treatment
facilitiy operators are advising customers via mailings never to put grease
into the sewage system at all, since it creates pipe blockages not to
mention lots of Biological Oxygen Demand.

The best option is to compost food in your own backyard along with all the
yard trimmings, food paper, and other organics such as cotton clothing.
I've done it for decades, and it's very satisfying, especially when combined
with growing food in the enriched soil you get when you actually use the
finished compost. My soil horizon in the food garden is now about eight
inches deep after fifteen years of soil amending with dozens of cubic yards
of humus. I'm also taking carbon that used to be in the air and putting it
into the soil, where it nourishes the soil critters and fungi that help
plants grow. The soil is much easier to work than the heavy clay that I had
to start with; no clods at all, and it holds water like a sponge.

Next best is to use curbside food and yard debris collection; these
centralized processing systems are proliferating all over the Bay Area right

Dan Knapp
Urban Ore, Inc., a reuse and recycling business in Berkeley, CA for 27

On Feb 28, 2008, at 11:54 AM, Kendall Christiansen wrote:

On Tuesday, the Wall Street Journal featured a report about the growing
international interest - with a focus on the EU - in the efficacy of food
waste disposers (aka garbage disposals) as an environmental management tool,
for immediate diversion of food scraps from the solid waste stream, and
relying on wastewater treatment plants to process the solids in fertilizer
products with energy recovery where possible. In particular, it noted the
experience of several cities that have intentionally opted for
disposer-based systems for food scrap management.

Given that the WSJ remains subscription-based, if you'd like a copy of the
article - as well as its Environmental Capital blog post on the same topic -
please let me know and I'll forward. If you would like access to one or
more of the reports referenced in the article, let me know that, too.

Kendall Christiansen

Gaia Strategies

151 Maple Street

Brooklyn, NY 11225

o: 718.941.9535; cell: 917.359.0725

the writer is senior consultant on environmental affairs for InSinkErator,
the leading manufacturer of residential and commercial food waste disposers,
and former Chair of NYC's Citywide Recycling Advisory Board

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