An assessment of anaerobic digestion capacity in Bangladesh

This work scopes the potential for existing common feedstocks to be used in existing types of anaerobic digester units to produce biogas in Bangladesh. A preliminary study identified three commonly occurring scenarios of smallholdings with cattle, poultry farms and daily cattle markets, which produce dung, poultry litter, and dung mixed with rice straw, respectively. This third feedstock is proposed as a novel and significant newly recognised prevalent source. The main study involved carrying out surveys of representative samples of each of these (N=125, 125, and 30) for the district of Gazipur in order to determine the distribution of herd and flock sizes, and thus the relevant biogas plant types and potential yields. The results were scaled up for nationwide figures, which approximated the total potential biogas energy from these feedstock types at 240×106 MJ (240 TJ) per day, or 66.7×106 kWh, which in principle could meet the current cooking energy requirements of 30 million people in Bangladesh. Of this, 70% of the potential energy from AD could come from cattle feedstock (with 87% of this from domestic-sized plant); 16% from poultry feedstock (with 63% of this from medium-sized plant); and 14% from rice straw bedding from cattle markets (all requiring very large or extremely large plant). There is potential for around 2 million domestic units, 340,000 medium units and 19,000 large units, as well as 500 very large units that might be more suited for larger users such as businesses, schools or hospitals.