Cover Image
close this bookBiogas Plants (GTZ, 1988)
View the document(introduction...)
View the documentAcknowledgements
View the documentPreface
View the document0. Biogas as appropriate technology
View the document1. Benefits and costs of a biogas plant
Open this folder and view contents2. The dgestion process
Open this folder and view contents3. Biogas plants
Open this folder and view contents4. Scaling of biogas plants
Open this folder and view contents5. Design of biogas plants
Open this folder and view contents6. Biogas utilization
View the document7. Planning, design and construction
View the document8. Appendix
View the documentBibliography
View the documentList of figures

0. Biogas as appropriate technology

A technology is appropriate if it gains acceptance. Biogas plants have hitherto gained little acceptance. Simple biogas plants have up to now presumably been inappropriate. Bicycles are appropriate: if a person buys a bicycle, he is proud. It is a sign of his advance, his personal progress. The bicycle is appropriate to the need for social recognition. If the person mounts the bicycle and falls off because he does not know how to ride it, it is not appropriate to the abilities of its owner. The person learns to ride and thus adapts himself to his cherished bicycle. The person goes to work on his bicycle. It is appropriate to his need for convenience and low-cost transport. The bicycle breaks down. The person has no money to spare to have it mended. He saves on other expenditure, because the bicycle is important for his pride and his convenience. He walks long distances to the repairer. He adapts to the needs of the bicycle.

The person can afford this expenditure without getting into economic difficulties. The bicycle is appropriate to his economic capacity.

A biogas plant is correctly operated and maintained if it satisfies the user's need for recognition and convenience. He for his part is then prepared to adapt to the needs of the biogas plant.

Biogas plants are appropriate to the technical abilities and economic capacity of Third World farmers. Biogas technology is extremely appropriate to the ecological and economic demands of the future. Biogas technology is progressive.

However, a biogas plant seldom meets the owner's need for status and recognition. Biogas technology has a poor image ("Biogas plants are built by dreamers for poor people". If you do not want to seem one of the poor, you do not buy a biogas plant. The image of the biogas plant must be improved.

The designer makes his contribution by supplying a good design. A "professional design" that works. One that is built in conformity with contemporary requirements and models. The biogas plant must be a symbol of social advancement. The biogas plant must be technically progressive.

A biogas plant as an investment is in competition with a bicycle or moped, a radio set or diesel pump, a buffalo or an extension to the farmhouse.

The economic benefit of a biogas plant is greater than that of most competing investments. However, the plant must also be worthwhile as a topic for the "chat in the market place".

So the design must not be primitive. So it must be well made.
So the gas bell must be attractively painted. So the gas pipe must be laid tidily.
So the fermentation slurry tank must be decently designed and constructed.
So giant pumpkins and flowers must grow around the plant.

A good biogas plant is appropriate. Appropriate to the needs of its owner and his abilities and capacity. It is appropriate to the necessities of the future

Fig. 1: A farmyard biogas plant This is a floating-drum plant with internal gas outlet. The gas pipe is securely mounted on the wall and leads directly to the kitchen. Ideally, as in this example, the digester should be located directly beside the animal shelter, which should have a paved floor. Urine and dung can be swept into the inlet pipe with little effort. The plant has a sunny location, and the vegetable garden is situated directly adjacent to the digested slurry store. The well is an adequate distance away from the biogas plant.