[Digestion] The relatively high cost of digesters.

Wed Dec 8 04:52:10 CST 2010

What Mr Karve is indicating is very important. Biogas can be a smart
solution in many places but one must always consider the local circumstances
and everything around and not just concentrate on the gas production. There
has to be suitable raw materials in sufficient quantities within reasonable
distance, one must consider the cost of collection and transport in monetary
terms or working hours and the same for distribution and eventual selling of
the gas and the residues. There are also environment effects to consider.
Gasification by digestion has beneficial effects but also some negative
impacts. When it comes to the use of digestion for treatment of waste there
are also competing alternatives like direct recycling, composting and
burning. Dried dung is for instance a good fuel and the ash still has the
minerals (in another form) although the nitrogene and all ligninous matters
are lost. The question of safety for small dispersed quite open plants in
rural areas in warm countries is different from large plants in densly
populated areas in cold countries where parts of the process must take place
inside enclosed buildings. In the academical world and on the political
level one must always try to look at a bigger system and move the system
boundries much beyond the plant itself. For instance if you are an academic
and just study digestion as a means for making electricity you have to move
the boundry out to encompass the whole electric system and look at the
electricity production and especially it’s consumption of marginal fuel, but
you must also look at the smaller system that may be just the local farm and
the farmers electricity bill. Similar ways apply if you look at other uses
of the gas and residues and be very careful when you want to use data and
experience from other places and countries. They might only be partly
relevant for the case you are working on. I we just look at Europe north
south east and west are different in many aspects. 

Björn Dahlroth

Sweden

  _____  

Från: digestion-bounces at lists.bioenergylists.org
[mailto:digestion-bounces at lists.bioenergylists.org] För Anand Karve
Skickat: den 8 december 2010 01:58
Till: paul.harris at adelaide.edu.au; For Discussion of Anaerobic Digestion
Ämne: Re: [Digestion] The relatively high cost of digesters.

Dear Paul and stovers,

I give here our experience in India about the rural dung based biogas
plants. India has about 140 million rural households and the government has
been making propaganda since 1950 for biogas plants. By the latest count, we
have today only about 3 million working biogas plants. That is just 2%
penetration of this technology. Due to increased mechanisation, the number
of draft animals is slowly dwindling, as a result of which the total number
of animals in the rural area is steadily going down. It is only the dairy
farmers and the owners of large poultries that have large quantities of
animal faeces to deal with. Due to lack of dung, many biogas plants have
stopped functioning. A dung based domestic biogas plant needs a daily input
of 40 kg dung mixed with 40 litres water (to make it into a pourable
slurry). In villages the women often have to fetch the water from a distant
source, carrying it on their heads. They have to bring about 25 to 30 litres
water every day as the drinking and cooking water for the household. This
quantity increases, if they have cattle. Bringing additional 40 litres for
the biogas plant is an added burden. So,although the housewife is told that
her life would be easier if the household gets a biogas plant, in actuality,
this technology increases her workload. 

Yours

A.D.Karve    

On Wed, Dec 8, 2010 at 8:17 AM, Paul Harris <paul.harris at adelaide.edu.au>
wrote:

G'day All,

One reason for the "high" cost of digesters is that "Westerners" seem to
have a preoccupation with complexity and large, centralised facilities -
which "we" expect to inflict on the rest of the world.

The small, simple, decentralised systems used extensively in China, India
and more recently Columbia, Vietnam, Cambodia and Bolivia and reported by
some members of this discussion group are making a big improvement to the
environment by providing convenient, clean fuel without deforestation or
fossil fuel depletion. They may not win on "biogas per unit digester volume"
or "throughput per day" and will not make corporate profits but they do lift
people from poverty, ease the grind of daily life and may well get more
biogas per unit of VS/COD, compared to "our" large units.

I agree you get what you pay for and there are bound to be improvements that
may need to be done, but it's also "horses for courses".

Happy digesting,
HOOROO

Mr. Paul Harris, Room S116b, Waite Main Building Faculty of Sciences, The 
University of Adelaide, Waite Campus, PMB 1, Glen Osmond SA 5064 Ph    : +61
8 8303 7880      Fax   : +61 8 8303 4386
mailto:paul.harris at adelaide.edu.au  
http://www.adelaide.edu.au/directory/paul.harris

CRICOS Provider Number 00123M
This email message is intended only for the addressee(s) and contains
information that may be confidential and/or copyright.  If you are not the
intended recipient please notify the sender by reply email and immediately
delete this email. Use, disclosure or reproduction of this email by anyone
other than the intended recipient(s) is strictly prohibited. No
representation is made that this email or any attachments are free of
viruses. Virus scanning is recommended and is the responsibility of the
recipient.

-----Original Message-----
From: digestion-bounces at lists.bioenergylists.org
[mailto:digestion-bounces at lists.bioenergylists.org] On Behalf Of Edgar
Blanco-Madrigal
Sent: Tuesday, 7 December 2010 10:51 PM
To: For Discussion of Anaerobic Digestion
Cc: digestion
Subject: Re: [Digestion] The relatively high cost of digesters.

In AD the universal principle applies:
"You get what you pay for"

You can build a cheap digester, and produce gas, etc. But you should not
pretend this in any way will be helping the environment, because to do that
money has to be committed in the whole operation.

SNIP

Please, do not peddle technology on the basis of its low cost, do it on the
basis of quality!

_______________________________________________
Digestion mailing list

to Send a Message to the list, use the email address
Digestion at bioenergylists.org

to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergyli
sts.org

for more information about digestion, see
Beginner's Guide to Biogas
http://www.adelaide.edu.au/biogas/
and the Biogas Wiki http://biogas.wikispaces.com/

-- 
***
Dr. A.D. Karve
President, Appropriate Rural Technology Institute (ARTI)

*Please change my email address in your records to: adkarve at gmail.com *

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/digestion_lists.bioenergylists.org/attachments/20101208/176122ac/attachment.html>