25-09-2014, 01:45 PM
Abstracts: BIOGAS About 50-60% of the Indian population lives in the rural parts of the country. This segment of the population is totally dependent on the use of biomass consisting of firewood, charcoal, twigs ,straw, crop residues, and cow dung to meet its energy demands for cooking and other domestic needs. It is estimated that the domestic biomass consumption for fuel is as high as 94% with very little use of modern sources of energy such as electricity and liquefied petroleum gas (LPG).The use of biomass as fuel has serious ill effects such as degradation of environment due to deforestation, loss of soil fertility due to diversion of animal manure which acts as fertilizer and various health hazards particularly associated with rural women and children. It is estimated that in the past 50 years the land covered by forest has dropped from approximately 50% to less than3%. Some experts attribute this mostly to forest clearing for cultivation and cutting trees for fuel, activities highly exasperated by population growth which is estimated to occur at an average annual rate of 2.6%. The current rate of deforestation is estimated to cover 200,000 hectares of land per year. Unless the rate of deforestation is arrested, India could lose all its natural forests in 20 years. The use of cow dung and other animal manure as a source of fuel might be considered responsible, at least in part, for reduction in soil fertility and reduced crop yield .Biomass combustion in households using traditional three stone fire place that lacks any provision for smoke exhaust exposes particularly women and children to smoke containing harmful products. Prolonged exposure to smoke is responsible for coughing, wheezing, acute respiratory infection, chronic obstructive lung disease, adverse pregnancy outcomes and lung cancer. Deforestation has made fire wood scarce as a result of which women and their young ones are forced to spend more time in fetching fire wood. In addition to being a heavy burden, fire wood fetching, in conjunction with other factors, is taking so much of the time of children that it may be said to be adversely affecting the literacy rate due to non-availability of time for education. In light of the reasons stated above, it is felt imperative that India develop an alternative energy source that ensures sustenance and availability of its fuel wood or derivatives there of Generation of biogas by anaerobic digestion of animal manure particularly cow dung, human excreta and kitchen waste is considered to be one such alternative. The technology of biogas has been successfully used in India and China since last 50 years and until now 3.8 million and 5million domestic biogas plants have been installed in India and China, respectively.