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[GreenYes] Re: Landfill methane recovery data


At 03:29 PM 3/1/2007 -0700, Eric Lombardi wrote:
>Hi John,
>
>I am on the Colorado Climate Project, and we are discussing the fact
>that we can't find any studies on "life-cycle methane emissions"
>from landfills. It seems that everyone keeps citing that 75% gas
>recovery rate for best-available-technology, but my understanding is
>that this number reflects only a point-in-time recovery rate when
>all systems are up and running at peak performance. My
>understanding is also that that special "point in time" begins and
>ends over a short amount of the time that buried organics are
>actually off-gassing.
>
>The lack of real data is probably attributable to the fact that no
>one has ever covered a landfill from day one and measured the gas
>generation over time.
>
>Have y'all in Wisconsin ever done a life-cycle estimate on the
>percent of gas that is actually captured?
>
>Eric

There is a report based on a look at a bunch of California landfills
that estimated a number on the order of 30 percent recovery. As I
recall it was based on calculations of how much gas should be
generated by the garbage, over what period of time (with respect to
the dumping) vs what was actually recovered.

As you say, nobody has apparently ever bagged a landfill and measured
accurately. But there are data from in-vessel anerobic digestion
processes that can be used to validate generation calculations. I
found it somewhat convincing and also disturbing in the low
percentage recovered. I don't recall the source or the authors but
can probably find it.

As far as I am concerned it confirmed my sense that landfill gas
burning should NOT be regarded as desirable from a carbon point of
view. Mostly because if you do that it may lead to support for
continued dumping, which will cause more gas to be leaked than recovered.....

am

>-----Original Message-----
>From: GreenYes@no.address [mailto:GreenYes@no.address]
>On Behalf Of Reindl, John
>Sent: Thursday, March 01, 2007 1:40 PM
>To: Dennis Sauer; GreenYes@no.address
>Subject: [GreenYes] Re: Landfill methane recovery data
>
>Hi Dennis ~
>
>I work for a county that owns a landfill and has very up-to-date
>technology for gas extraction and energy production, with revenues
>of over a million dollars a year.
>
>When we did our food scraps recovery study, this very question came
>up and our study's conclusion was that the removal of food would
>have negligible impact on gas recovery at the landfill. (We used the
>EPA LandGEM model.)
>
>On the other hand, removal of food from landfills will cut down on
>odors and the attraction of birds, flies and other vectors. And, for
>waste generators, it means that materials don't need to be set out
>frequently for collection (I set out material only 2-3 times a year).
>
>Best wishes,
>
>John Reindl, Recycling Manager
>Dane County, WI
>
>-----Original Message-----
>From: GreenYes@no.address [mailto:GreenYes@no.address]On
>Behalf Of Dennis Sauer
>Sent: Thursday, March 01, 2007 2:16 PM
>To: GreenYes@no.address
>Subject: [GreenYes] Landfill methane recovery data
>
>Does anyone have recent data or studies relating to the capture rate
>of methane from landfills? As we expand our food scrap diversion
>programs we have received criticism that we are stealing fuel from a
>co-generation facility at our regional landfill. I realize that in
>dry tomb landfills, any reduction of methane from removing food
>scraps is negligible due to the rapid decomposition of food
>scraps. This has been answered by critics who state that the latest
>landfill and methane recovery technology does capture methane from
>food scraps and all of the methane generated by a landfill. I have
>read one study that states: despite claims of 70-75% recovery rates,
>the actual amount being recovered is more like 20%. Can anyone
>direct me to additional information to back up this data?
>
>
>
>Thanks,
>
>Dennis
>
>
>
>Dennis Sauer
>
>Compost Specialist compostspecialist@no.address
>
>Central Vermont Solid Waste Management District
>
>137 Barre St, Montpelier, Vermont 05602
>
>802-229-9383 Ext. 303
>
>800-730-9475(Vt only)
>
>802-229-1318 fax
>
><http://www.cvswmd.org>www.cvswmd.org
>
>
>
>
>
>
>
>
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