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[GreenYes] Re: Landfill methane recovery data

At 04:07 PM 3/1/2007 -0800, you wrote:
>Hi folks ~
>This has been a very useful exchange, and yet skirts around a
>practical question: doesn't it make sense that if the objective is
>to generate and harvest methane a controlled system, both controlled
>in its feedstock and controlled in its scale and design, would make
>more sense than a landfill?
>Alan Muller mentioned a study of a digester ("... there are data
>from in-vessel anaerobic 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..."). It
>would be useful for Alan to find and forward this study. It sounds
>from the findings ("low percentage recovered") that the digester in
>the study was not designed to control methane? Not sure however why
>a study of a digester could be used to "validate" landfill capture...

Just that if you do anerobic digestion in a vessel, sealed and under
control, you can keep track of what comes out, and compare the actual
gas output with predictions based on chemical calculations. If you
do it in a pit or pile that leaks top, bottom, and sideways, you can
only guestimate ....

>I have felt for some time that we need some information to smoke out
>the claims of landfill operators that they are preventing climate
>change by harvesting methane. This is real greenwashing.

My main concern is this: Yes, it is better to capture as much as
possible rather than just let it escape. (Landfill gas is a lot more
than just methane, There is all sorts of nasty stuff in it. Methane
itself has no particular odor.....). But if setting up a capture
system, which in reality only captures a fraction of what is coming
out, convinces people that landfilling has now become "green" and
acceptable, "greenwashing" is happening big-time.

The problem gets worse when landfill gas power (we call it "garbage
fume power," see for
some discussion) is subsidized as "green" or "renewable" energy,
and/or is used to meet "renewable portfolio standards"
(quotas) This creates a political link between electricity vendors
and dumpers, and encourages continued dumping.

Many people and orgs aren't sure what to make of this issue.....


>At 03:04 PM 3/1/2007, Wolbert, Brad - DNR wrote:
>>[Here's a reply I attempted to post earlier, only to find out I
>>couldn't post to the entire group. I think that's been fixed; we'll see.]
>>Dennis -- on the technical question, I can only point to one
>>specific study, and it was a conference presentation, not a
>>refereed published article. For what it's worth, it's at
>>Unfortunately, no one knows what the correct values are for the
>>model inputs that were used, so I would take the conclusions with a
>>very large grain of salt. Still, it may be useful in understanding the issue.
>>My own discussions with researchers in this field lead me to
>>conclude that there is no firm consensus on system collection
>>efficiencies of methane from landfills, and it is highly variable
>>in any case. There are periods in the life of landfills when there
>>is no gas collection system installed or operating. Even when the
>>gas system is running, in the best of circumstances, there is an
>>open working face where landfill gas can escape. I tend to believe
>>that lifetime capture efficiencies are closer to the higher percent
>>range you cite below in cases where the landfill is recovering gas
>>for flaring or utilization. Probably during the operation of the
>>gas systems, the capture efficiency is even higher. Otherwise
>>these facilities would stink like crazy, all the time. Well-run
>>landfills are generally able to control their odor problems most of the time.
>>Two other points are important. The food scraps very likely have
>>more value outside the landfill, as compost, than buried in the
>>landfill, but you'd need a life-cycle analysis to prove it. Maybe
>>there's one out there, I don't know. Also, given the realities of
>>landfilling (lots of plastic, lots of places where moisture doesn't
>>reach) some of those landfilled food scraps won't break down for
>>many years, long after the gas utilization system is gone; that
>>fraction has no value as fuel at all.
>>Brad Wolbert
>>Hydrogeologist - Wisconsin DNR
>>From: GreenYes@no.address [mailto:GreenYes@no.address]
>>On Behalf Of Alan Muller
>>Sent: Thursday, March 01, 2007 4:44 PM
>>To: Eric Lombardi; Reindl, John; 'Dennis Sauer'; GreenYes@no.address
>>Subject: [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?
>>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.....
>>>-----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?
>>>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
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>>>It has removed 1193 spam emails to date.
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