[Digestion] DOC Biogas potential

Thu Aug 17 07:32:48 CDT 2006

Concerning the BMP additives, I know that one of the basics in this field is studies from Speece & Mc Carty (1964) and Woliin et al. (1963).
Also, resazurin is added to detect oxygen contamination (pink when oxidized), and sodium sulfide is added to provide a reducing environment.
Pardes & Levebvre, 2001 gave also a formula to know for each element the quantity to add per g MVS of the waste. It takes into account the impact of each element of the nutritive solution on the biomass production.

Regards

O. LEMAIRE

-----Message d'origine-----
De : digestion-bounces at listserv.repp.org [mailto:digestion-bounces at listserv.repp.org] De la part de alastair ward (IGER-NW)
Envoyé : jeudi 17 août 2006 12:11
À : David Fulford; Arjun Gupta; digestion at listserv.repp.org
Objet : Re: [Digestion] DOC Biogas potential

I agree with David that a digester is the best way to find the methane potential, but this raises a question that has bothered me about the BMP assays in the past: The method uses a nutrient and trace element mixture to support the microbes, but if a feedstock is deficient in one or more of these, the BMP assay will not take this into account. If something is missing in the feed then I would like this to be reflected in the results. Does anybody know why the assay uses these additives?

Regards,

Alastair Ward

-----Original Message-----
From: digestion-bounces at listserv.repp.org
[mailto:digestion-bounces at listserv.repp.org] On Behalf Of David Fulford
Sent: 17 August 2006 09:30
To: Arjun Gupta; digestion at listserv.repp.org
Subject: Re: [Digestion] DOC Biogas potential

Arjun Gupta and listers,

The experiences of Vivekananda Kendra - NARDEP in southern Tamil Nadu and also Dr Karve of ARTI in Pune (see http://www.ashdenawards.org/technical_summary06_india_vk_nardep and
http://www.ashdenawards.org/technical_summary06_india_arti) show that deoiled cake of all oil seeds (including castor) is a very good feed for

biogas plants. The biogas production is very much higher than that for cattle dung (Dr Karve claims 40 times).

The best way to test the biogas potential of a feedstock is to put it into a small biogas plant. The ARTI design is very cheap and mobile (made from two spun HPDE plastic water tanks), so would be an ideal test bed. My own experience of testing feedstock samples is that the standard batch digestion tests do not give the same results as using a semi-continuous process. A well-adapted semi-continuous plant is surprisingly robust and

can cope with a wide range of feedstocks and a wide range of dilutions and total solid content. Obviously, if there is too much water, it just washes out the bacteria, so you need to use a UASB or anaerobic filter, which are designed to clean up polluted water. The upper limit for total solid content, though, seems very high and is usually constrained by the desire to pour the feedstock in and out of the plant. Mix a known amount of the feed to be tested with the regular feed of the plant (cow dung, food
wastes) and use it for several days and measure the increase in gas production over the quantity measured when the plant is fed steadily with the standard feed.

regards,

David Fulford

At 10:20 17/08/2006 +0530, Arjun Gupta wrote:
>Hello,
>    Has anyone experienecd using Castor De-oiled cake to produce 
>biogas. Also what are the basic analysis tests to be done on a 
>potential biogas feed stock to determine it's biogas potential, 
>dilution and solids in output slurry percentage. How does one use these

>figures. Thankyou. _______________________________________________
>Digestion mailing list
>Digestion at listserv.repp.org
>http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org

*** Dr David Fulford, Energy Group, Engineering Building       ***
***     School of Construction Management and Engineering      ***
***      The University of Reading, Whiteknights,              ***
***    Reading RG6 6AY, UK      Tel: +44-(0)118-378 8563,      ***
*** Fax: +44-(0)118-931 3327 E-mail: D.J.Fulford at Reading.ac.uk ***  

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