BIOHYDROGEN PRODUCTION FROM CASSAVA WASTEWATER AND DOMESTIC SEWAGE IN AN ANAEROBIC FLUIDIZED BED REACTOR

Abstract

This study addresses hydrogen production in two anaerobic fluidized bed reactors (AFBRs) that were fed with cassava wastewater and domestic sewage. The reactors were operated at hydraulic retention times of 4-3 h (AFBR 1) and 4 h (AFBR 2). The maximum hydrogen yields (HY) and the maximum hydrogen production rate (HPR) were, respectively, 0.93 mol H2.mol glucose-1 and 1.69 L.h-1.L-1 (AFBR 1) for the AFBR 1, and 2.03 mol H2.mol glucose-1 and 0.95 L.h-1.L-1 for AFBR 2. The hydrogen content ranged from 2.25 to 23.25% (AFBR 1) and from 7 to 50.75% (AFBR 2). The hydrogen content increased significantly when the amount of domestic sewage decreased, that is, higher concentrations of cassava wastewater in the substrate favors the hydrogen production. Acetic acid was the predominant metabolite that was soluble in both reactors, indicating that the hydrogen production rate and the hydrogen yield made the acetic acid pathway predominant. The association between cassava wastewater and domestic sewage favored biohydrogen production satisfactorily.