A mesophilic cascade anaerobic digester with low-ratio digestate recirculations
A cascade anaerobic digester consists of a series of completely stirred tank reactors (CSTRs) and is applied for enhanced bioconversion of waste activated sludge (WAS).This cascade process performance can be optimized applying digestate recirculation. In our present study, we investigated the effects of low recirculation ratios, varying between 2% and 10% of the influent flow, on the hydrolysis and bioconversion of WAS in a four-stage mesophilic cascade process.