Treatment of concentrated wastewater in thermophilic anaerobic-aerobic moving bed biofilm reactors

The moving bed biofilm reactor was used for the thermophilic (55ºC) anaerobic-aerobic treatment of molasses water. The amount of anaerobic biomass in the reactor reached 4.6 g SS/L after 22 months of operation. Anaerobic biofilm growth was highest at loading rates of 2-5 kg COD/m3d. Removal rates up to 4.1 kg COD/kg VSS·d were obtained at loading rates up to 7.0 kg COD/kg VSS·d. Volumetric removal rates of 3.9 kg COD/m3d were achieved at loading rates up to 9-9.5 kg COD/m3d in the anaerobic reactors. The amounts of aerobic biomass varied be tween 3.8 and 9.7 g SS/L. A maximum aerobic removal rate of 2.0 kg COD/kg VSS·d was achieved at a loading rate of 3.4 kg COD/kg VSS·d. Volumetric removal rates of 3.3 kg COD/m3d were achieved at loading rates up to 9.0 kg COD/m3d in the aerobic reactors.