[Digestion] Just starting

Thu Nov 28 10:09:55 CST 2013

Frans, Hello,

Kyle has made some useful comments. One of the early pioneers in the UK 
used chicken dung as the main feed for his biogas system. There are 
plenty of biogas systems in Bangladesh that use chicken dung. It helps 
to start the system with some cattle dung (it contains the right 
microbes), but you do not need more when it is working properly.

The effluent that come from the plant is a very good fertiliser, is 
smell-free and does not attract flies. You could dry it, bag it and sell 
it. A bag digester will work, there are plenty of examples, but it will 
not last as long as masonry systems. There are some good biogas 
engineers in East Africa who can build these, but you need to look for 
them. If you have already ordered a plastic tube, you should start with 
that. Details of how to use it can be found at: 
http://www.adelaide.edu.au/biogas/poly_digester/.

A 35 deg.C system is much easier to use than a 55 deg.C system. Kyle is 
a bit vague on temperature, it is better to run at close to 35 deg.C. 
However, it is very expensive to find a way to heat a digester, so most 
people run them at ambient temperature. The compost will be improved if 
it is left to mature. If it is fairly liquid when it comes from the 
plant, it can be absorbed into dry biomass (e.g. straw) and allowed to 
compost further. This will help kill pathogens and weed seeds.

Best wishes,
David
davidf at kingdombio.com

******************************************************
Dr David Fulford CEnv MEI, 15, Brandon Ave, Woodley, Reading RG5 4PU
        Tel: +44(0)118 969 5039 Mob: +44(0)7746 806401
Kingdom Bioenergy Ltd, www.kingdombio.com, davidf at kindombio.com
                                 Skype Identity: djfulford

------ Original Message ------
From: "Kyle Schutter" <kyle at takamotobiogas.com>
To: "For Discussion of Anaerobic Digestion" 
<digestion at lists.bioenergylists.org>
Sent: 28/11/2013 10:05:54
Subject: Re: [Digestion] Just starting
>Hi Frans,
>
>Good questions. From experience with smaller scale systems with chicken 
>dung mixed with cow dung let me give a first attempt at an answer:
>
>a) this should work well
>b) the volume of the dung will increase because you mix the chicken 
>droppings with water. and the effluent, while having a lower BOD than 
>the influent, will not be low enough to dump. You will still have to 
>find a way to use the droppings as fertilizer and now that the effluent 
>is semiliquid it will be hard to transport.
>c) this may solve part b) above, but I have no experience with this and 
>I don't know if there are machines for this.
>
>1) It can be used
>2) You will have to kickstart at first, but you shouldn't have to 
>afterwards
>3) KISS (Keep It Stupid Simple) probably applies here. I think the 
>tubular bag digesters would be best for you as they are cheap and easy.
>4) As long as the average ambient temperature is above 20˚C year round 
>you will not need to heat (even above 15˚C is okay. In Kenya we operate 
>digesters at this temperature with no problem though 15˚C is too cold 
>to start a digester we have found). Heating will just increase cost. If 
>you want to get more gas out of the system, just get a larger bag 
>digester. They are really cheap. Q energy in Uganda sells 300 meter 
>cubed digesters for around $10,000. 150-300 meter cubed digester should 
>be a good size for you. (I am guessing your chickens produce 40 to 100 
>g of droppings per day per chicken)
>5) True, but only really at 55˚C which is a very difficult system to 
>maintain.
>
>Another consideration is that chicken droppings have lots of pebbles 
>usually and I would guess this won't be a problem, though you may have 
>to empty your digester every few years to get the pebbles out.
>
>Others probably have more experience than me.
>
>Kyle
>Founder and Director of Technology
>Schutter Energy Ltd.
>+254 703113383
>kyleschutter (skype)
>www.takamotobiogas.com
>
>
>
>On 28 Nov, 2013, at 10:21 AM, Frans Somebody wrote:
>
>Hi All.
>Although I have read a lot, I have no practical experience & would 
>appreciate any ideas & suggestions.
>I have 37 000 laying hens but very limited access to cow dung.
>The reasons for starting digestion is, in order of priority;
>a) Fly control. Too many chemicals being used,  which is not working 
>anyway.
>b) Manure disposal.The dairy farmer who has taken it for 11 years is 
>changing to sugar cane.
>c) Gas production. To assist in the drying of the slurry, for storage & 
>sale.
>As a start & a test, I have ordered a heavy re-enforced plastic tube of 
>approx 1.8m round X 10m long.
>Mh chalenges are;-
>1) I can find no information on pure chicken droppings. Can this be 
>used?
>2) If I have to 'kick-start' the bacteria with cow dung, will it be 
>necessary to re-do this at regular intervals?
>3) The most effectice system? Fixed dome, floating dome, tubes or?
>4) The recommended temp is 37 to 42C, others have suggested that much 
>higher temp, (50), produce more gas.
>5) The advantage of higher temp could be a reduction in unwanted 
>bacteria & seeds in the effluent.
>Thank you for allowing me on your forum.
>Frans (Swaziland)
>
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>for more information about digestion, see
>Beginner's Guide to Biogas
>http://www.adelaide.edu.au/biogas/
>and the Biogas Wiki http://biogas.wikispaces.com/
>
>
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