by NICK ROSEN on OCTOBER 8, 2012 - 2 Comments in self-sufficiency
His latest piece of kit, a methane gas burner that takes his poo from the composting loo and turns it into cooking gas, was provided by StreetKleen, a Manchester organisation. One pound of poo can produce about one cubic foot of gas enough to cook a day’s meals for 4 people.
But what the presenter of Grand Designs did not tell you was that a biogas digester only works in relatively warm weather. For the next six months of the year, Kevin will be sitting on a pile of poo that is way too cold to produce cooking gas.
Biogas, or methane, is a clean-burning, “green” fuel used for heating and cooking, transport and power generation — and you can make it yourself. The video above shows you how.There are two types of digester, batch digesters and continuous digesters. Batch digesters are filled with a mixture of organic wastes and water (slurry) and sealed, and emptied again when they stop producing gas. Continuous-load digesters are fed a daily load of slurry, with gas and digestion wastes produced continuously.
The “natural gas” piped to millions of homes is also methane, though it’s purer than biogas. Chemically they’re the same, but that’s where the resemblance ends.
Landfills and tips that leak methane are a major contributor to human-caused global warming.
Like carbon dioxide, methane is a greenhouse gas — it’s over 20 times more damaging to the environment than carbon dioxide. Making and using biogas is part of the natural cycle, and it doesn’t contribute to global warming.
But in turning your poo into cooking gas, you won’t be releasing any biogas into the atmosphere, and when you burn it, the only emissions are carbon dioxide and water vapour.
Methane is also called marsh-gas — it’s what causes the flames sometimes seen flickering over marshes at night, the source of much mediaeval fear and superstition. But you will see no flames from making biogas because it all happens inside a closed digester.
Biogas is free but its a little less valuable than Natural gas. It contains about 55-65% methane, 30-35% carbon dioxide, and some hydrogen, nitrogen and other impurities. Its heating value is around 600 BTU. Natural gas contains about 80% methane, with a heating value of around 1000 BTU.
Biogas digestion works best at 25 to 35 deg C, 77-95 deg F. Add the sludge and supernatant to your compost pile. Biogas digestion makes the best sense when it’s coupled with hot aerobic composting, then nothing will be wasted. Also, the heat in an active compost pile can be harnessed to produce a hot water supply, which means you can use the compost to keep the digester at working temperature during cold weather.
If you keep poultry, there’s a way to make better use of the sludge, though it doesn’t need very much of it to make high-protein poultry feed.
“Most opinions indicate that anaerobic fermentation is very sensitive to operate and difficult to control.” — “A Biogasification System at a Dairy”, Proceedings of the Oklahoma Academy of Science, 56: 18-23 (1976), M. R. Brulé and S. S. Sofer
Don’t be put off though, you can do it. Study the resources below carefully, decide what’s best for you in your particular circumstances, and go ahead.
Biogas as motor fuel
Engines for Biogas (GTZ-GATE, 1988) — 164-page pdf ebook (6.6 Mb download)
Gas – 10 Cents per GALLON – YES!!! — Peter H. Weis, Vancouver.
“You can run your car, if you wish, on fuel which would cost you about 2.5 cents per litre – or about 10 cents per gallon – and get 5 miles per gallon more than you do now. And there will be much cleaner exhaust — plus a very substantial reduction of carbon dioxide emissions as well, which will be a considerable contribution to the reduction of the greenhouse effect.”
Biogas as fuel, the right choice for valorization of organic waste! — Biogasmax, October 5, 2007
Resources – with thanks to http://journeytoforever.org/biofuel_biogas.html
See also Humanure
Beginner’s Guide to Biogas, maintained by Paul Harris at the
University of Adelaide
The Digestion email discussion list, “For Discussion of Anaerobic Digestion”
Digestion Archives — from August 2004. No search function, but the full text of each month’s discussions can be downloaded (zip file) and searched on your hard-disk.
Methane Digesters, by Beth Doerr and Nate Lehmkuhl, ECHO Technical Note, 2001, 2008 — 7-page pdf
Biogas, Practical Action, Technical Information Online
The Biogas Digest, from GTZ, the German 3rd World development agency — in English:
Vol. I: Biogas Basics
Vol. II: Biogas Application and Product Development
Vol. III: Biogas Costs and Benefits / Biogas Programme
Vol. IV: Biogas Country Reports, GTZ-GATE, 1999
Engines for Biogas, GTZ-GATE, 1988 — 164-page pdf ebook (6.6 Mb download)
Put a chicken in your tank — Eccentric British inventor Harold Bate found a way of converting chicken droppings to biogas and running his car on it. He claimed chicken power would run a car faster, cleaner, and better than gasoline. Bate said he’d driven his 1953 Hillman at speeds up to 75 mph without the use of gasoline.
Methane Digesters For Fuel Gas and Fertilizer, With Complete Instructions For Two Working Models — by L. John Fry, Santa Barbara, Calif. 93103, © 1973, Eighth Printing (out of print). Excellent manual on making and using methane — biogas. Fry developed his techniques while running a pig farm in South Africa, designing the first full scale displacement methane plant. Good information on integrating biogas production with gardening and farming, and with pond-culture food production. Designs for a Sump Digester using 55-gal oil drums and an Inner Tube Digester. With thanks to Kirk McLoren.
Interview: L. John Fry
Interview: Ram Bux Singh
Nepal Biogas Plant — Construction Manual. Construction Manual for GGC 2047 Model Biogas Plant. With Dutch and German support, Nepal’s Biogas Support Programme has built 95,400 biogas plants in 10 years, with potential for half a million more. These are fixed dome biogas plants, designed in Nepal. Sizes are household-scale from 4 to 20 cubic metres. The feedstock is cattle dung and water (but other feedstocks will work just as well). For instance, the 4-cubic-metre plant requires input from 2-3 cattle, the 10-cubic-metre plant needs 6-9 cattle. This manual includes full construction details, plans and data. With thanks to Olivier Morf.
Jean Pain: France’s King of Green Gold — In the 1980s Frenchman Jean Pain built a home-made power plant that he claimed supplied 100% of his energy needs. The core of the system was a 50-ton compost mound, three metres high and six across, made of pulverized tree limbs and underbrush. Buried inside the compost was a 4-cubic-metre sealed steel tank 3/4-full of the same compost, producing methane — bio-gas. Tubes connected the tank to a pile of 24 truck-tyre inner tubes, the gas reservoir. Pain said he used the gas to cook all the food, fuel a truck and produce electricity, via a methane-fuelled internal combustion engine that turned a generator. The truck ran off two gas bottles on the roof. Another tube ran from a well and into the heap, with 200 metres of tubing wound round the tank; Pain said the water emerged at 60 deg C at 4 litres a minute, which was enough for central heating, and for the bathroom and the kitchen. The compost heap continued fermenting for nearly 18 months, and then yielded 50 tons of natural fertilizer. (With thanks to Ramjee Swaminathan.)
A Chinese Biogas Manual — Popularising Technology in the Countryside, edited by Ariane van Buren from the original by the Office of the Leading Group for the Propagation of Marshgas, Sichuan (Szechuan) Province, Peoples’ Republic of China, technical editor Leo Pyle, translator Michael Crook, Intermediate Technology Publications, 1979, original publishers: Science Publishing House, 1976, China, ISBN 0 903031 65 5 — 12.6Mb pdf
Compost, fertilizer, and biogas production from human and farm wastes in the People’s Republic of China. Ottawa, IDRC, 1978, ISBN 0-88936-140-l, 94p. Editors Michael G. McGarry and Jill Stainforth, translated by Lee Thim Loi from “A Compilation of Data on the Experience and Sanitary Management of Excreta and Urine in the Village”, published by The People’s Hygiene Publisher, People’s Republic of China. 7.8Mb pdf
Biogas technology in the Third World: a multidisciplinary review, Andrew Barnett, Leo Pyle, S. K. Subramanian, IDRC, Ottawa, Ont., 1978, ISBN O-88936-162-2, 132 p. 14.4Mb pdf
Biogas Systems in lndia, by Robert Jon Lichtman, VITA/COSTED, ISBN O-86619-167-4, 1983, 142pp. 11.7Mb pdf
Biogas and Waste Recycling — The Philippine Experience, by Felix DI Maramba, Sr., 1978, Liberty Flour Mills, Philippines, 32.3Mb pdf
Biogas plants in animal husbandry — a practical guide, by Uli Werner, Ulrich Stöhr, Nicolai Hees, GATE/GTZ, 1989, ISBN J-528-02048-2, 157 pp. 17.2Mb pdf
Tubular Plastic Bio-digesters in Tanzania, Viet Nam, Zimbabwe & China, selected & edited by John Furze, 1997/1998/2002, University of Aarhus, Denmark, 257pp. 24.3Mb pdf
How To Install A Polyethylene Biogas Plant, by Francisco X. Aguilar, Agronomic Engineer, Royal Agricultural College, Cirencester (991 kb pdf)
Biogas: What it is; How it is made; How to use it — FAO Better Farming Series 31 (read online at Alex Weir’s CD 3rd World online library):
Biogas 2: Building a Better Biogas Unit — FAO Better Farming Series 32 (read online at Alex Weir’s CD 3rd World online library):
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