Re: Briquettes of beef manure

[CAVM@aol.com]

Dr. Karve,

(Keep in mind that I am an accountant, not an engineer.)  Dr. Robert Farmer of Baylor Univ showed me the briquettes which he had made as part of a demonstration.  I was very impressed with the quality of the briquettes.  Dr. Farmer tells me that the BTU value was higher than the locally produced coal and the ash was very low.

I have not worked with briquettes but I have worked with anaerobic digestion.  These briquettes were made from dried cattle manure (dung) as I understand it.  With anaerobic digesters we recommend a separator precede the digester to remove some of the solids.  A fixed film digester after the separator is usually a good investment if the local electric rates justify its cost.  If not, the liquid can be cleaned for reuse as wash water for the manure in the milking areas and feeding pens.

Dr. Farmer also has a technique for growing and processing algae in the liquid fraction of the waste.  This would supplement the protein found in the other feed ingredients for cattle, hogs or poultry.  Besides the protein feed ingredient the algae go a long way in polishing the effluent.  I think that Dr. farmer also has recommendations regarding the use of the algae as fuel instead of feed, if desired.

Cornelius A. Van Milligen
Kentucky Enrichment Inc.
Ag Project Managers
CAVM@AOL.com

adkarve@pn2.vsnl.net.in writes:

> Dear Corneleus,
> The dung cakes that are used as fuel in rural India are made manually from a mixture of fresh dung and agricultural waste such as stover of cereal crops. They possess a calorific value of about 2600 Kcal per kg. Your message mentions beef manure.  As I understand it, manure is a product that one gets after dung and other waste matter on the farmstead is fermented, generally under anaerobic conditions. The carbon content (that is the combustible matter) of cattle dung is lower than that of biomass consumed by the cattle, and that of manure would be even less. Our manually produced dung cakes generally do not produce a flame. They smolder.  They also have a high ash content. How do your briquettes burn? Do they produce a flame or do they glow like charcoal? Would your product be comparable to peat or lignite briquettes? Have you thought of producing biogas from cattle dung? If the carbondioxide can be removed from biogas, the pure methane remaining behind is equivalent to natural gas in its calorific value and burning properties. The slurry left behind after biogas fermentation can go back to the soil as manure. Therefore biogas is environmentally the cleanest option of converting cattle dung into fuel, however it is difficult to transport, whereas briquettes can be easily transported.  
> A.D.Karve