Micro-Biogas Plants Help Communities to Produce their own Energy

The urban planner and energy activist T. H. Culhane from the US together with participants of the Global Campus built a first small biogas plant in Tamera.

With the organic kitchen waste of one day enough gas for two hours of cooking can be produced. It is a solution for using renewable energies also in rainy regions or seasons.

Shredded organic kitchen waste is mixed with water in a hermetically sealed container and then given to stomach bacteria to be eaten. After a few days already the gasometer in the gas container, mounted above the fermenter, climbs; biogas is being passed onto to the user through a thin hose, and we can light a gas lantern or cook. From each bucket of kitchen residues gas for two hours of cooking results, and on the side valuable liquid fertilizer for the garden is produced.

T. H. Culhane could hardly believe that it is so easy it when he first met Dr. Anand Karve from the ARTI-Institute two years ago in the Indian industrial town of Poona. In the micro biogas plants the specialist used kitchen residues instead of the usual cow dung. The conclusion he draws: "It is 400 times as efficient as the system with cow dung!"

For years, T. H. has been working in the slums of Cairo and other African countries in order to develop decentralized solutions for energy production together with the local people. At first his plan was to bring decentralized solar energy into the  slums. "But the people there did not only suffer from the lack of energy, they also had another giant problem: They were drowning in garbage. What to do with the continuous horrible smell and the misery of the organic waste where rats prosper and children become sick? For composting there is often not enough space."

With the biogas idea organic waste becomes a valuable raw material. In the poorest settlements in the African bush and in slums T. H. experimented together with the inhabitants. They used what they found – buckets, plastic containers, hoses, old gas cookers – to build a biogas fermenter, This improvisation capacity T.H. also used in Tamera, and together with the enthused participants of the Global Campus he built a functioning biogas system within two days.

The bacteria do in the fermenter exactly what they do in cow stomachs: digesting food. This is also why organic kitchen waste is much more suitable for biogas plants than compost toilets or pure vegetable mass. The general rule is: The more diverse the food for the fermenter the better. With a few shovels of cow dung, diluted in warm water the biogas system is initiated, the bacteria find their food and start to work.

The second product resulting from a biogas plant is a fertilizer, a concentrated nutrient solution containing all the elements that made the plant grow in the first place. In many aspects it is even more valuable than compost because from the closed container no ammonium escapes and all the nitrogen is kept as fertilizer.

"The only delimiting factor is the fact that the bacteria in a smooth 1000 liter container can digest only one bucket full of kitchen waste. The bacteria do not swim in the compost soup, they live on firm surfaces, on the bottom and on the walls. In a settlement in Kenya the inhabitants had an idea: we could increase the surface in the fermenter. Inspired by the way the inside of a cows stomach is folded we now build drainage pipes with big surfaces into the container a to increase the number of bacteria and thus the efficiency of the fermenter."

Tamera's chief biogas engineer Martin Funk: "We have been cooking for months with biogas, it works perfectly. I am enchanted, T. H. is a true master of  LowTech – the simple technological solution."

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