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Biogas

 

Biogas

In April of 2010, the construction of a biogas system began in Testfield 1. In the summer of 2011, a second system was built and connected with the first. Both phases of construction took place within the framework of a training for students of the Global Campus: Representatives of global peace projects—for example the peace community “San José de Apartado,” in Colombia, the “Peace Favela” in São Paolo in Brasil, and Philipp Munyasia from Otepic in Kenya—were able to participate and therefore learn the principles of these systems. This knowledge can prepare the way for construction of these biogas systems, with adaptations to local conditions where they live, and contribute to the energy autonomy of their peace projects.


Above all, the integration of a biogas system into the Testfield improves the situation when there is relatively little sun: in winter, and in the early mornings and evenings of summer. With biogas, the kitchen can remain in service through the rainy winter season, during which direct solar power is not enough. We will also experiment with powering a refrigerator and a generator with biogas. This is a possible solution to the problem of refrigeration and cooling in countries with tropical heat and frequent cloud-cover, such as Colombia. In these tropical regions, with plentiful biomass but little direct sunshine, biogas can be the main source for energy, also for cooking.


The system works with many different kinds of biomass; we generally “feed” it with ground kitchen and garden scraps. These so-called waste products are transformed into a source of 1) biogas and 2) living, liquid fertilizer, both of great value. A true “win-win” situation; and a simple, decentralized solution for many.


In contrast to more the more ordinary, large-scale biogas systems, we do not need high-energy biomass from the kinds of large grain- or corn monocultures that require expensive fertilizers and are in direct competition with food-production. Our systems are also not connected to industrial animal-raising, as is the case of systems that use animal manure for gas production. The biogas system in the Testfield is integrated into an ecological and human system to which we can give a full “yes!”


Our system combines two digesters:

One design, a long-established style from Nepal and China, has been for the first time adapted to a European and vegan context: http://journeytoforever.org/biofuel_library/methane_nepal.html


This is why additional elements were introduced, especially temperature control. The temperature of the system is maintained with the aid of solar collectors.


The second digester was built next to the Solar Kitchen, with an urban planner and energy activist from the USA: T. H. Culhane (http://solarcities.blogspot.com). T. H. Culhane studied with Dr. Anand Karve of the ARTI Institute in Poona, India. http://www.arti-india.org/index.php?option=com_content&view=article&id=45


To feed the mini-biogas systems he developed, Dr. Anand Karve used kitchen waste instead of the usual animal waste. His conclusion: “It is 400 times more effective than the system with cow manure.”


For years, T. H. has been working together with the local people in the slums of Cairo and in other African countries, to develop decentralized solutions for energy supply. He often does his research with local residents in the poorest settlements, in the African bush, and in slums. They use what is available—buckets, plastic canisters, hoses, old gas cookers—to assemble a whole system: the biogas digester, an attached gas reservoir nearly as large as the digester, the inlet for kitchen waste, the outlets for gas and liquid fertilizer, and the cooker and other devices that use the gas.


In the Tamera Testfield, the two digesters—6,000 liters and 3,000 liters—can process 90 liters of “biomass slurry” daily (this represents approximately 10 kg of kitchen waste, mixed with warm water). The kitchen produces this much material every day during busy times. We can then expect to cook with biogas for 18 hours per day on a small flame, or 9 hours on a large flame. We keep track of the development of the system, collect the basic data (temperature, “feeding,” pH, and gas output) to be able continue to develop and improve the digester, leading to further optimized systems. We are happy to make this knowledge available widely, and we are happy to take on students who want to work with this system and accompany this research.


Brochures about the construction of a biogas system: (from T. H. Culhane, Tamera, und Valerio Marazzi - ARCò, Italy)

Biogas Digester (pdf) (English)
Digestor Biogas (pdf) (Portuguese)


Videos and songs about the work of T. H. Culhane:

http://youtube.com/tculhane
http://melodic-mnemonics.blogspot.com/2009/11/making-biogas-is-gas-gas-gas.html
http://melodic-mnemonics.blogspot.com/2009/01/talkin-trash.html

Thanksgiving Song (More and More):
http://melodic-mnemonics.blogspot.com/2008/08/as-we-sow-so-shall-we-reap.html

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