[Stoves] [biochar] First report from Phnom Penh

[Alex English]

Dear Anand,
What was the particle size of the char that you added to achieve this 
effect? Have you tried different sizes?

Thanks,
Alex

On 21/03/2013 8:53 PM, Anand Karve wrote:
> Dear Paul, Ron  and others,
>  I was instrumental in the development of an urban biogas plant, which 
> does not use cattle dung but uses food waste as feedstock. One kg dry 
> weight of starch, sugar, cellulose, protein or any other kind of human 
> food produces about 1 kg biogas. My biogas plant could normally accept 
> only 1gram (dry weight) food waste per litre capacity of 
> digester.  Our experiments in which the biogas digester was filled 
> with charcoal made it possible to increase the quantity of food waste 
> to three grams per litre, with three times as much biogas becoming 
> available from the same plant. This worked for about three months and 
> then the higher efficiency was no longer available. It is a common 
> observation, that a biogas plant works better, if chemical fertilizers 
> are added to the feedstock. I have been thinking about this and it 
> appears to me that it was the minerals in the biochar, that were 
> contributing to this phenomenon. After the organisms in the biogas 
> plant had consumed the minerals, the higher efficiency was no longer 
> available.
> The same phenomenon might be responsible for the higher yield in 
> fields provided with biochar.
> Yours
> A.D.Karve
> O