LAUSR

A full-scale sand/gravel bioreactor system was constructed to treat turkey processing wastewater. The system was designed to treat 757,000 L day -1 at a surface application rate of 6 cm day -1 . Twelve 25 x 55 m sand bioreactors cover 1.6 ha on the plant property site. Construction cost was $1,426,000 (2011-2012) and operating costs were $57,600 per year. Normalized to volume of wastewater treatment, the estimated (2013) capital and operation cost is $1.03 m -3 . The plant began discharging effluent in 2013. Throughout 30 months, the plant has met all effluent requirements for CBOD 5 , TSS, and fat, oil, and grease (FOG). FOG was always below the detection level of 5 mg L -1 in the treated effluent. Ammonia is removed by the sand/gravel bioreactors through the summer months. During the winter/spring months, supplemental ammonia removal with an ion-exchange system is used to meet effluent standards. The low cost of the sand bioreactor system makes it suitable for small-scale meat processors.