Impact of Small Anaerobic Digester on Household Economy of Bangladeshi Livestock Farmers

An extensive survey was performed covering all the regions of the country to find out the overall impacts of bio-digester on the economy of livestock farmers. Five districts were selected; ten farmers with having bio-digester of 3.2 m3 on average and ten farmers who have no bio-digester were selected from each district. Through direct interviewing and farm monitoring, all farm characteristics, i.e., diurnal biogas production, power generation, cooking time, income and expenditures, farmer’s gross earnings, and manure management practices data were collected accordingly. Descriptive statistics and student t-test was made to express the comparison response of the farms by using XL and SPSS software. It was observed that the owners of anaerobic digesters earned significantly (p < 0.001) more than the traditional farmers by selling animals and biogas (1715 & 306; 1146 & 0.00 USD, respectively). Not only that, by selling milk and fresh manure, the owners of bio-digester harvested more (p < 0.05) annual income than non-bio-digester farmers (4162, 3408 & 60.91, 44.63 USD, respectively). Though the expenditure of farmers having digester was high, but in a single fiscal year, they earned more (p < 0.05) profit than the conventional farmers (USD 4329 & 2842, respectively). However, owners of bio-digester used 67.2 % of their produced manure for gas production. Regarding storing manure as biomass and using it for cooking purposes significant difference (p < 0.001) was observed that was also reflected in the total manure management system of a farm. The farmers having no bio-digester stored 71.95% of their total manure in solid form, whereas the farmers who had bio-digester only stored 20.4% of their manure, which made a significant (p < 0.001) difference. From the biogas chamber, in an average one farmer used a gas stove for 4-5 hours and a gas lamp for 6-8 hours, which saved at least the expenditure of 18 USD per month/household. The notable thing was that the bio-digester alone contributed 7% to those farmers’ gross economy by producing gas. It can be recommended that the rural householders could generate power by installing bio-digester and turn a small bio-digester as a beneficial avenue of their household economy.