[Digestion] biogas from restaurant oil & food waste

[Anand Karve]

sorry, my message got sent before I could do proof reading. I complete
the sentence about yield of biogas from castor beans. 1 g macerated
castor beans yielded about 800ml biogas.
Yours
A.D.Karve

 On Wed, Oct 5, 2011 at 3:47 PM, Wayne Zschech
<waynezschech at calvarychapel.com> wrote:
> G'day All!
>
> The waste vegetable oil we collect from the restaurants has up about 10-12%
> water and food waste in it.  We heat the oil up to 65oC and then drop this
> 'soup' out from the bottom.  We want to utilize this waste about 1,5-2,0
> tonnes per month as a feedstock for biogas production.  We also end up with
> about 500kg of rancid fats/oils that we can't use for biodiesel production.
>
> I understand that both the soup and the rancid fats should be able to give
> me lots of gas but don't know how to calculate the needed reactor volume.
> I'm also concerned that the fat will float at the top of the reactor and
> cause problems. Could anyone give some reactor design tips for these
> feedstocks?
>
> Also is it possible to produce a digestate that can be used as animal feed
> or feed supplement?  from this waste? from restaurant food waste in
> general?  We have long winters and I don't want to have to store the
> digestate as fertilizers for many months if I can produce a product local
> pig farmers can use.  It has been suggested that I should make batch type
> reactors so as to be sure that all the organics have been digested before
> 'packaging' or storing it.  Are pathogens likely to be a problem?  Should I
> consider thermophilic temperatures? I've read that heating such waste to
> 70oC for 1 hour is the industry standard.
>
> What other problems can I expect to encounter.
>
> Any input would be appreciated.
> Many blessings,
> Wayne
>
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>
>
>



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