Anaerobic digestion of thin stillage of corn ethanol plant in a novel anaerobic baffled reactor

In this study, the performance of a conventional anaerobic baffled reactor (ABR) and a novel configuration of hybrid ABR for the treatment of thin stillage was evaluated. The hybrid ABR achieved the chemical oxygen demand (COD) removal, sulfate removal and methane yield of 97-94%, 94-97% and 294-310 mL CH4 g−1 CODremoved, respectively at organic loading rate (OLR) of 1-3.5 kg COD m−3 d−1. On the other hand, the value of COD and sulfate removal and methane yield for the conventional ABR were 75-94%, 67-76% and 140-240 mL CH4 g−1 CODremoved, respectively at OLR range of 1.1-1.8 kg COD m−3 d−1. The enhanced performance and robustness of the novel ABR was demonstrated to be the result of incorporation of solid/liquid/gas separators into the configuration of the conventional ABR, leading to reduced biomass washout, higher solid retention time and significantly improved phase separation.