Saf_WEDCThesis-2009-2010-SAF.pdf (1.96 MB)
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Household biogas systems in low income rural regions

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thesis
posted on 25.08.2020, 11:00 authored by Sören Säf
The theory of biogas is simple and brilliant – convert dangerous waste into benefits. The gas produced can be used for cooking, lighting, engines and other applications, providing benefits such as a smoke-free indoor environment, reduced amount of time for household chores, lit environment for home-work, fuel for pumping water and much more. And, after the process, the previously dangerous waste that was put into the biogas plant is now a fertilising bio-slurry. Used in agriculture it will increase the crop yield and by re-circulating the nutrients. The transformation effect, from dangerous waste to bio-slurry, also has a benefit that has received more attention during the last years. While traditionally using mostly cattle dung and other animal waste, the biogas plant can also be fed with human excreta, thus acting as a sanitation solution as well. The Millennium Development Goals, set up to end poverty, include such things as improved health, more time for income generating activities, opportunities for school work, increased food production and proper sanitation (UN, 2010). In theory, biogas technology would be very suitable to help fulfilling these goals that has been set up by the world community. In fact, UNESCO (United Nations Educational, Scientific and Cultural Organization) regarded biogas as a ―promising approach to decentralised rural development‖ as early as the 1970’s (DaSilva, 1979) and SNV (the Netherlands’ development organisation), in the late 2000’s, say that ―SNV firmly believes households raising livestock are able to benefit from domestic biogas plants for the production of sustainable cooking fuel and potent organic fertiliser‖ (van Nes, 2005: 2). Still, the big household biogas boom is yet to come. In 2007 the author was involved in building a prototype of a household biogas plant in Nyanza Province, Kenya. When the prototype was finished it seemed to be a success – it was producing gas, a nearby kitchen could use the gas, a local farmer was in need of the effluent (slurry leaving the digester) as fertiliser, people seemed to enjoy using the toilet connected to it, and the construction cost was relatively low. However, two months after leaving the area, people stopped using the system. What went wrong? Had the digester started to leak? Was it too much of an effort to keep it running? Did the gas not ignite? Was the previous option just more convenient to use?

History

School

  • Architecture, Building and Civil Engineering

Research Unit

  • Water, Engineering and Development Centre (WEDC)