[Digestion] Digestion Digest, Vol 10, Issue 24

[Steve Verhey]

Here's a more brief version of Alex's really useful comments, in case anyone wants to reply to the list.

Date: Thu, 30 Jun 2011 11:05:40 -0600


From: alex at sistemabiobolsa.com


To: digestion at lists.bioenergylists.org


Subject: Re: [Digestion] Digestion Digest, Vol 10, Issue 24





Randy Gecko's question was the cost of commercializing the fertilizer.  This is more of a concrete number (or series of numbers depending on scale).  Value
 is a much harder calculation, at least for us in Mexico.  In some 
areas, the value of this
fertilizer has taken on the value of the tradition chemical fertilizers 
it is displacing (with a slight discount).  In other areas where demand 
for organics is growing fast, the value is even higher.  In areas where 
the fertilizer has not been proven (or where
people evaluate it on pure NPK) the value is lower, or non-existent.  
Therefore, I think it would be useful to talk about costs of techniques 
for commercialization, while at the same time talking about the 
independent process of creating value of the product
through outreach, research, and general promotion.  





Regarding costs and process, we have been filtering the digestate with a
 simple screen, and then giving it a short residence time in barrels 
where it tends to stratify.  We take the substrate off the top for 
foliar feeding and adding to irrigation water, and
the sludge is applied to the land directly.  This has a very small cost 
of time for each farmer, but as usual, we are dealing with a much 
smaller scale them most here on this list (read: small farm digesters). 
 





This year is very important harvest year for us as we will be reporting 
the results of a number of test plots that isolated different fertilizer
 types and techniques, essentially competing head-to-head with common 
fertilizers in the region.  This has been paired
with a long-term series of laboratory tests isolating the components of 
the fertilizer.  Our initial results have shown that a single digester 
will put out very consistent fertilizer quality and type as long as the 
inputs stay similar (although they absorb
a decent amount of variation).  However, between digeters in the same 
region with the same feedstock, there can be a huge amount of 
variation.  This means that our efforts to begin creating a fertilizer 
market for the digestate require some sort of field testing
to qualify it and "certify" it.  That may not have to happen very 
frequently for a single digester, but it should cover nearly all of the 
digesters for a given program (unless you can show regional similarities
 we apparently do not have).  





Proving and demonstrating the value of the fertilizer has been 
determined by us to be the NUMBER ONE most important aspect for the 
biogas program (not actually the biogas!), and as mentioned here will be
 an important factor for pushing AD technology in general. 
Through the Latin American Biodigester Group we have started a working 
group whose aim is to conduct unified multi-country research on the 
quality and use of the "biol" as a fertilizer.  I would be very 
interested in seeing who else from this group may want
to contribute or participate in this process.  We would ultimately like a
 field guide for the testing, decision making and use of the biol that 
can be widely utilized.  





I look forward to any comments or motivations, or, if anyone has something like that already, please share!  





Cheers





A     





On Thu, Jun 30, 2011 at 4:58 AM, Christine McKiernan <cmckiernan93 at gmail.com> wrote:


Digestate as Fertilizer





Per Gordon Gecko's comments (aka Randy Mott)  what are the potential 
values of the separated factions of treated digestate?  If this 
treatment is done on a large scale how are each of the 3 factions 
removed 'easily'?  Just wondering about implementation.


Thanks,


Christine McKiernan












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