Biogas Production through Anaerobic Digestion of Tannery Solid Waste

Annually about 85,000 tons of raw hides and skins are estimated to be processed for leather production in Bangladesh. Tannery generates huge amount of solid and liquid wastes. Anaerobic digestion (AD) is a potential treatment to stabilize waste and produce biogas for renewable energy. The aim of this study was to investigate the potential of AD of tannery solid waste (TSW) generated from the pre-tanning operation and to compare the effect of cow dung as the substrate to TSW. For the reaction with TSW by mixing with different substrates, biogas production was observed starting on 4th day with a steady increase. The cumulative gas production from each of the test reactors operating at the various organic loading of tannery solid waste, domestic sewage, and cow dung were different. This study shows an optimal AD process of TSW by mixing with different substrates for the obtained optimum C/N ratio and also for the high volatile solids (VS). The COD removal rates for the series of 5 reactors (R1, R2, R3, R4 and R5) were 48.75, 50.84, 46.07, 45.94 and 47.78% respectively. Maximum COD removal was achieved from reactor R2 where maximum gas was also produced.