Mobilization and impacts of bio-gas technologies

At present, energy and fertilizer requirements of many of the developing countries are largely met by locally available, non-commercial sources, such as firewood and farm wastes. Extensive use of firewood is one of the factors that can lead to deforestation. When organic farm wastes are burnt, soil nutrients, which should return to soil, are lost and this can severely affect agricultural production. The problem of efficient utilization of these locally available resources, therefore, needs to be studied in a systematic manner. As an option for efficient utilization of local resources, bio-gas plants are considered, taking India as a case study. In these plants, animal dung and agricultural byproducts are utilized to obtain both methane and fertilizer through anaerobic fermentation. This is an example of appropriate technology for rural environments, which requires low investment, which does not need highly skilled labor and which can be operated with local materials and self-help in the 576,000 villages of India. The economic benefits to a family using a bio-gas plant and the impact of its widespread acceptance on a national scale are evaluated. It is felt, however, that the scope of such individual family bio-gas plants is likely to be limited for a number of reasons. To realize the potential of bio-gas fully, village plants of about 200 m3 capacity for approx. 100 families are needed.