BACKGROUNDDespite sound technological improvements, huge water consumption and the associated wastewater discharge remain one of the major environmental challenges in the brewing industry. The aim of this study is therefore to investigate the performance of a mineral filled pilot scale trickling filter to treat brewery wastewater. A trickling filter is superior over the other conventional wastewater treatment processes in terms of cost and environmental friendliness therefore it is recommendable particularly for low income countries. RESULTSPilot scale plant experiments were made to evaluate the trickling filter aerobic and anaerobic biofilm systems for removal of organics and nutrients from brewery wastewater at different hydraulic loading rates. The trickling filter had an average efficiency of (86.53), (95.25), (69.93) and (41.03)% for biochemical oxygen demand (COD), biological oxygen demand (BOD5), total nitrogen (TN) and total phosphorus (TP), respectively, as the flow rates changed from 900 to 1100 L day(-1)at an influent COD concentration of 600 mg L-1. A linear regression model revealed that there is very high correlations between mass loading rate and mass removal rate. The results of this study suggest that in addition to significant values for nutrient removal efficiencies, effluent value in the range 50-120 mg L-1 COD can be achieved using the trickling filter at the design hydraulic load and organic load of 8.36 m(-3) m(-2) day(-1) and 0.75 k g m(-3) d(-1), respectively. CONCLUSIONOrganic substances and nutrients in brewery wastewater can be handled in a cost-effective and environmentally friendly manner using the gravel-filled trickling filter. (c) 2014 Society of Chemical Industry