Abstract
The effect of hydraulic retention time (HRT) on the anaerobic digestion of wastewater containing methanol was investigated in a continuous experiment using three CSTR digesters. Three digesters continuously fed by artificial wastewater containing methanol were operated at a HRT 2,5 and 15 days, respectively. No accumulation of volatile fatty acids were observed in each reactor during the operation. The removal efficiency of COD ranged from 90% to 92% . Methane-producing activity tests suggest that direct methanol-utilizing pathway is predominant in the methane fermentation of the methanol. The results of cloning analysis revealed that sarcina-shaped cells beloning Archaea were predominant in the two reactors with HRT 2 days and HRT 15 days. FISH analysis results suggest that Methanosarcina-targeted cells were predominant in the reactors with HRT 2 days and HRT 15 days.
