This research investigated the feasibility of coarse/fine sand filtration for removing organic materials from turkey processing waste-water. Sand filtration was tested with three organic and hydraulic loadings. Six two-layer sand bioreactors were in three groups, each with 5 cm layer of pea gravel at the bottom to support layers of fine sand (46 cm) and coarse sand (15 cm) to a height of 66 cm. The bioreactors were inoculated with a mixture of 20% (vol/vol) of wastewater lagoon sludge, 40% (vol/vol) of turkey processing wastewater, and 40% (vol/vol) of BOD5 dilution water before starting the column operation with turkey processing wastewater. The wastewater contained 1270 +/- 730 mg COD/L and was applied to each sand bioreactor at hydraulic loading rates of 264, 132 and 66 L/m(2)/day. Each group comprised duplicate columns with the identical hydraulic loading. A commercially available detergent, Ivory (TM), was added to the wastewater at 0.04% (wt/vol). Maximum treatment efficiencies were reached within a week. The removal of TOC and BOD5 was > 94% during 80 days of column operation at low and medium hydraulic loading rates (<= 132 L/m(2)/day). The removal at the highest hydraulic loading rate (264 L/m(2)/day) declined after the appearance of a black zone in the top layer of fine sand on day 30 for one reactor and day 50 for the other. The sand filtration in this study represents a feasible treatment for turkey processing wastewater and its efficiency and the life span of the process are associated with the extent of hydraulic loading of the sand bioreactors. (c) 2006 Elsevier Ltd. All rights reserved.