Biodigesters in Latin America and the Caribbean
by George Dafermos, Panos Kotsampopoulos, et al.:
"Biodigesters are natural systems that take advantage of organic waste from agricultural activities, mainly animal manure, to produce biogas (fuel) and organic fertiliser through the process of anaerobic digestion. Biogas can be used as fuel for cooking, heating or lighting. In large installations, biogas can be used to power a motor for electricity generation. The fertiliser was initially considered an insignificant byproduct, but is currently considered to be as important as the biogas, as it provides communities with a fertiliser that strongly improves crop yield. Low-cost biodigesters (such as the low-cost polyethylene tube type shown in Figure 6) are considered to be an appropriate technology due to their low (initial) cost of investment, simple operation, basic maintenance requirements and accessibility to both small and large producers.
Low-cost digesters have been implemented in developing countries since the 1980s. They were first designed by Pound in Taiwan in 1981. Based on that design, the flexible tubular continuous flow digester, initially designed in 1987 by Preston in Ethiopia, Botero in Colombia () and Bui Xuan An in Vietnam (1994), adapted the digesters for tropical climates. In 2003, Martí-Herrero Botero’s design adapted the digester to cold climates in the highlands of Bolivia, adding a greenhouse (Figure 7) with adobe walls with high thermal inertia and insulation from the ground using local materials. This technology is accessible in countries such as Colombia, Ethiopia, Tanzania, Vietnam, Cambodia, China, Costa Rica, Bolivia, Peru, Ecuador, Argentina, Chile and Mexico.
Similar projects have been implemented in Asia; the SNV Netherlands Development Organisation has driven major national programmes in Bangladesh, Cambodia, Nepal, Vietnam, Indonesia and other countries. China and India have their own national programmes, while in Africa, the SNV Netherlands Development Organisation and the German Society for International Cooperation (GIZ) are promoting programmes of a similar scope (focusing mainly on Tanzania, Kenya and Rwanda). In the countries of Latin America and the Caribbean, where no national programmes exist yet, many organisations and individuals have set up projects in Mexico, Honduras, Nicaragua, Costa Rica, Cuba, Colombia, Ecuador, Peru, Bolivia and Brazil. In Bolivia, in particular, the EnDev-Bolivia project for “Access to Energy” run by the GIZ is currently the largest project in Latin America on biodigesters. Aside from raising public awareness around the benefits of biogesters, the project, which has installed more than 400 of them in recent years, is running the Centro de Investigación en Biodigestores Biogas y Biól (CIB3) research centre and is offering training courses on designing digesters and social project management.
Of those projects, perhaps the most interesting is the Network of Biodigesters in Latin America and the Caribbean (REDBioLAC), as it brings together various institutions involved in the research, development, dissemination and implementation of low-cost biodigesters in nine Latin American countries. Its members include manufacturers of biodigesters, NGOs, research centres and universities with the objective of sharing information and experiences, identifying technical, environmental, social and economic barriers, suggesting ways to spread the biodigester technology in different countries, systematising research and dissemination among partners and encouraging actions that influence policies related to biodigesters.
Through the above case studies we have come to identify a set of enabling conditions from which we can draw several general principles for the development of policy recommendations aimed at strengthening the development of a post-fossil fuel society that respects the Rights of Nature." (http://peerproduction.net/issues/issue-7-policies-for-the-commons/peer-reviewed-papers/transforming-the-energy-matrix/)