An efficient combined system based on modified two-phase anaerobic digestion (MTPAD) combined with a biological aerated filter (BAF) is proposed to treat wastewater generated in the production of Dioscorea zingiberensis CH. Wright (DZW). The pilot-scale experiments showed that both organics and sulfates at high concentrations could be removed satisfactorily due to the advantages of the MTPAD in eliminating the negative effects of sulfide inhibition to methanogens. Simultaneous nitrification and denitrification (SND) in the BAF resulted in efficient removal of COD and NH(4)(+)-N. UV-vis analysis showed that the organic compounds with aromatic structures were biodegraded effectively in the anaerobic process. GC-MS analysis revealed that furfural compounds in the influent were also biodegraded, leaving fewer compounds remaining in the final biological effluent. High efficiencies of COD removal (99.3%) and NH(4)(+)-N removal (93.7%) were achieved, and the quality of the final effluent met the National Discharge Standards of China for DZW wastewater. (C) 2009 Elsevier Ltd. All rights reserved.