Enhanced anaerobic digestion of brewers’ spent grain: effect of inoculum, poultry manure application and iron (iii) chloride supplementation on biogas production and its kinetics
Tunde David Edunjobi, Oluseye Omotoso Agbede, O. A. Aworanti, Ademola Oyejide Adebayo, S. E. Agarry, Oyetola Ogunkunle, Opeyeolu Timothy Laseinde
Abstract
Abstract The brewery industry generates a huge quantity of brewers’ spent grain (BSG) which can pose waste disposal and pollution problems. Anaerobic digestion of BSG, a recalcitrant lignocellulosic waste, is slow but can be enhanced by bioaugmentation, biostimulation and co-digestion to obtain a higher biogas yield. Hence, the effect of inoculum from brewery wastewater sludge (BWWS), iron (III) chloride (FeCl 3 ) and co-digestion with poultry manure (PM) on the production of biogas from BSG was investigated. Cumulative biogas and biomethane yields of 588.19 NL/kgVS and 400.34 NL CH4 /kgVS, respectively, were obtained from a slurry consisting of a blend of 60% BSG and 40% PM plus 15 mg L -1 FeCl 3 in BWWS, after 30 day retention time at 37 o C. However, mono-digestion of BSG in only water yielded 402.17 NL biogas /kgVS and 262.86 NL CH4 /kgVS. The synergistic effects of inoculum from BWWS, FeCl 3 and poultry manure on anaerobic digestion of BSG resulted in 46% and 52% increases in biogas and methane yields, respectively, compared with BSG mono-digestion. The biogas and biomethane production kinetics were well described by the dual pooled first order, logistic and modified Gompertz models.