This research study focused on the biotreatability of waste beer in an anaerobic environment. A comparison of two bioreactors, ASBR (anaerobic sequencing batch reactor) and UASB (upflow anaerobic sludge blanket) reactors, was performed. The experiments were carried out in the two reactors under identical conditions at room temperature and 351 C under organic loading rates (OLRs) from 2 to 20 kg chemical oxygen demand (COD) m(-3) day(-1). The results show that the performance in the ASBR was better than that in the UASB reactor without a recirculation system at the two temperatures under all organic loading levels. In the ASBR, soluble COD reductions of 95 to 57% and 93 to 70% were obtained as the OLR increased from 2 to 20 kg COD m(-3) day(-1) at room temperature and 350 C, respectively. In the UASB reactor without a recirculation system., the soluble COD reduction was 78 to 49% and 80 to 65% under the same increase in OLR as the ASBR at room temperature and 35 degrees C, respectively. Methane production was measured in the ASBR at both temperatures. Results for methane production were close to the expected yields of 0.39 m(3)/kg COD removed for an OLR of 2 to 6 kg COD m(-3) day(-1), and lower than the expected valuesfor an OLR of 8 to 20 kg COD In m(-3) day(-1). Therefore, anaerobic treatment of beer is sustainable by both reactors if the organic load is limited to 6 kg COD m(-3) day(-1). (c) 2004 American Institute of Chemical Engineers Environ Prog,
