Effects of disc rotational speed and submergence on the performance of an anaerobic rotating biological contactor

Abstract

Effects of disc rotational speed (ω) and disc submergence (Ω) on the system performance of a four-stage anaerobic rotating biological contactor (AnRBC) for treating high-strength organic wastewater were investigated to establish optimal operating conditions. Results of tracer study showed that the flow was more mixed when the AnRBC system was operated at a higher ω or at a lower Ω In the steady-state operating condition, the stage chemical oxygen demand (COD) removal efficiency increased as ω increased in the range of 0–12 rpm. The opposite trend was observed at ω values above 12 rpm. The optimal ω values are between 6 and 24 rpm with the overall COD removal efficiencies ranging from 70 to 78%. Results of disc submergence showed that the stage COD removal efficiency increased with an increase in Ω The overall COD removal efficiencies were 64, 70, and 78% for 40, 70, and 100% disc submergence, respectively. The AnRBC system appears to be an effective process for treating high-strength organic wastewaters under operating conditions of 12 rpm and 100% disc submergence.