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[GreenYes] Re: Apples to Apples

The DST analysis includes a long list of emissions, and, of course, a variety of assumptions. We are going to have the analysis re-done to correct some of the assumptions, but, perhaps more importantly, we are also assessing the relative impacts of the various types of emissions. For example, we will assign values for the relative harm of VOCs compared to methane comprared to CO2 compared to NOx compared to SOx compared to mercury, etc, etc. While it is not really possible to do an "apples to apples" comparsion for the various types of emissions, an environemental valuation approach will estimate harmfulness in common units. Jeff Morris has done similar studies and I encourage folks to go to his web page ( and look at his reports under "Subscriber Access", which is available at no cost.

The PhD thesis that I spoke about is:

Author: <,+Carol.> Diggelman, Carol.
Title: Life-cycle comparison of five engineered systems for managing food waste / by Carol Diggelman
Publisher: c1998.
Description: 2v, [xxx, 571 leaves] : ill. ; 29 cm.
Internet Links: <>
Notes: Typescript.
Thesis (Ph.D.)--University of Wisconsin--Madison, 1998.
Includes bibliographical references (leaves 552-571)
Also available on the Internet.
OCLC: (OCoLC)40277820
Subjects: Dissertations, Academic Civil and Environmental Engineering.


<> Location: Memorial Library UW Madison Theses Basement North
Catalog: UW Madison
<> Call Number: AWB D5727 C376

Ms Diggleman is currently on the faculty at the Milwaukee School of Engineering and continues her work in this area.


-----Original Message-----
From: Alan Muller [mailto:amuller@no.address]
Sent: Friday, August 11, 2006 4:52 PM
To: Matthew Cotton; 'GreenYes'; Reindl, John
Subject: Re: [GreenYes] Apples to Apples

At 02:09 PM 8/11/2006 -0700, Matthew Cotton wrote:

John -

The DST also looks at the VOCs from landfills, and concludes that they are much lower than from composting sites. I don't know why -- which was the basis for my question; I would like hard data, rather than 'gut instincts'.

I think the discrepancy is that organic materials are decomposed aerobically at a composting facility, and anaerobically at a landfill (that's pretty much a fact, not gut instinct). Comparing a composting facility to a landfill on strictly one parameter (like VOC emissions) is not reasonable or particularly useful. Yes, the VOC emissions will be lower at a landfill, especially non-methane emissions, in the same way that a landfill generates (and releases) a lot more methane than a composting facility.

Air quality managers concerned with ozone attainment will tend to pay a lot of attention to "VOCs" as a category. But it is a broad category and we need to consider what they actually are and their harmfulness.....

Do the comparative numbers include assumptions regarding gas recovery from landfills?

The biochemistry going on in composting does produce some NOx. See, for example:

I think it is only realistic to recognize that there are significant air emissions associated with composting. In most cases these, put in perspective, will be the lesser evil. But there likely will be places where open-air composting is not ideal.

I look forward to learning more about this.


Alan Muller, Executive Director
Green Delaware
Box 69
Port Penn, DE 19731 USA
fax (302)836-3005
greendel@no.address <>

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