Start-Up of an Anaerobic Moving Bed–Biofilm Reactor and Transition to Brewery Wastewater Treatment

Abstract

Two 4-L anaerobic moving bed–biofilm reactors (AMBBR) with different quantities of cubic media (25 and 35% by volume) were examined. Reactors were fed synthetic protein-based feed and both were shown to be capable of treating up to 20 kg/m3 day of chemical oxygen demand (COD), achieving 80% COD removal. Beyond that load the performance began to decrease. The maximum biogas production observed was 9.25 m3 CH4/m3 day at an organic loading rate (OLR) of 20 kg COD/m3 day. The methane composition varied between 60 and 70%. Averaged methane yields of 0.36±0.07 m3 CH4/kg COD removed and specific removal rates from 0.4 to 20 kg COD/m3 day were achieved. At the maximum OLR above 20 kg COD/m3 day, the specific surface area activity was calculated as 98 and 75 g COD/m2 day in the 25 and 35% reactors, respectively. Kinetic tests performed at the maximum OLR revealed that free-floating suspended biomass contributed to no more than 2.5% of the total removal. The reactors were also capable of treating brewery wastewater, reliably attaining 80% COD removal with methane yields of 0.36±0.06 and 0.39±0.03 m3 CH4/kg COD from the 35 and 25% reactors, respectively.