Treatment of turkey processing wastewater with sand filtration

This research investigated the feasibility of coarse/fine sand filtration for removing organic materials from turkey processing wastewater. 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/m2/day. Each group comprised duplicate columns with the identical hydraulic loading. A commercially available detergent, IvoryTM, 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/m2/day). The removal at the highest hydraulic loading rate (264 L/m2/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.