[Digestion] landfill vs. AD

[Pablo Izquierdo]

An AD process is quicker, e.g. days rather than days in landfill, and 
the capture efficiency is much larger. Eventually, it will mean more 
fossil fuel energy being displaced.It has also the potential benefit of 
using the digestate as fertiliser. Artificial fertilisers require energy 
to be produced and have problems associated with nitrous emissions. 
Quote from DEFRA in the UK 
(http://www.defra.gov.uk/farm/environment/climate-change/index.htm):

"67% of the UK’s nitrous oxide emissions, a greenhouse gas 310 times 
more potent than carbon dioxide, also come from agriculture, partly from 
livestock manures but mainly from the use of artificial fertiliser."

I hope this helps.
Pablo.

Russell Thomas wrote:
> Never thought I'd say this, seeing as I've been working in the landfill gas
> to energy sector for the last 15 years . . . the collection efficiency on a
> landfill won't be as high as in a digester, due to the mix of other non
> organic wastes, the leachate levels, the variable natural decomposition in
> the site and the overall collection efficiency of the extraction system.
>
>  Overall, you will get a better bang for buck through controlled and
> accelerated decomposition, enhancing collection efficiency by digesting it.
>
>
> -----Original Message-----
> From: digestion-bounces at listserv.repp.org
> [mailto:digestion-bounces at listserv.repp.org] On Behalf Of Jason Perry
> Sent: 27 April 2007 16:55
> To: digestion at listserv.repp.org
> Subject: [Digestion] landfill vs. AD
>
> Dear AD Listers,
>
> I may have asked this question in some form before, but I thought I'd 
> rephrase it.
>
> Consider a rural town in the Northeastern US. If you had a choice 
> between 1) sending the town's domestic food waste to a landfill that 
> collects its gas and runs a generator, or 2) sending it to a central AD 
> that co-digests food waste and dairy manure and runs a generator, which 
> do you think is a better use of the food waste in terms of energy 
> production? Assume similar transport schemes between the two.
>
> Many thanks,
> Jason Perry
>
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