[Digestion] Biogas production

[Deepak D. G.]

Hallo Kyle,

I use HDPE water tanks. The reactor is 650 ltr and the gas collector 
drum is 550 ltr. I am feeding the reactor with kitchen waste (mostly 
banana skin, papaya skin, vegetable leaves) of 1.5 kg per day with 5 
liter of water.

I get about 300 liter of gas every day.

I think you just need to wait for the antibiotics to lower and you might 
want to change the feed for a while.

Namaste,
Deepak



On 11/14/2012 04:00 AM, digestion-request at lists.bioenergylists.org wrote:
> Message: 1
> Date: Tue, 13 Nov 2012 10:44:10 +0300
> From: Takamoto<kyle at takamotobiogas.com>
> To:Digestion at bioenergylists.org
> Subject: [Digestion] Biogas production
> Message-ID:<B1C98E63-C3B8-401D-97AD-71CFB78F3607 at takamotobiogas.com>
> Content-Type: text/plain; charset="utf-8"
>
> Dear Biogas List,
>
> I have been testing a plastic (LLDPE) floating drum digester with cow dung and found that the biogas production was lower than expected (pH 7, 19?C) at around 0.5 cubic meters of biogas per day at 67% methane. The reactor volume is 3.2 cubic meters. I discovered that our dung supplier had recently used the antibiotic Tetracycline for a few of his cows so there is a chance of contamination, though at this point, I feel like the antibiotic concentration would be very low and should not affect gas production. Does anyone have experience with the effect of antibiotics? Also, what gas production should I expect from a 3.2 cubic meter reactor that I add 40 kg of cow dung to per day (plus 40 kg of water)? If I assume 15% TS and 80% of TS are VS then the Organic Loading Rate is around 1.5 kg -VS/m3/day and our specific methane yield is 0.07 m3 CH4/kg-VS and our digester efficiency is 0.1 m3 CH4/m3 reactor/day. Does this sound reasonable?
>
> I have also been reviewing research articles on gas production from cow dung but the results vary widely and sometimes I am not sure if the reported results are accurate. Also, research papers often use CSTR (continuously stirred tank reactors?) at 37?C which makes comparing their results to my results rather difficult. We are getting a new load of non-contaminated cow dung today to see if that makes a difference. I'll let you know.
>
> I am sure this topic has been discussed before, so I am sorry if I have repeated the topic. I am newish to the forum so I haven't seen anything on this yet.
>
> Thanks for your advice,
>
> Kyle
> Managing Director
> Schutter Energy Ltd.
> www.takamotobiogas.com
>