Recovery of Sand Bioreactor Performance through Resting Following Treatment of Turkey Processing Wastewater

Abstract

This research investigated the impact of resting on the performance of sand bioreactors treating turkey processing wastewater. Sand bioreactors received either raw turkey processing wastewater or a mixture of raw turkey processing wastewater and 0.04% of Ivory detergent. Two- and three-layer structured sand bioreactors were operated indoors at a hydraulic loading rate of 132 L/m2/day at 60 min dosing intervals. First sand bioreactor operation was terminated when excessive ponding occurred. After resting for 35 days at 264C, the second sand bioreactor operation was performed under similar operational conditions. Higher treatment efficiencies of TOC and BOD5 and greater total removed TOC and BOD5 were achieved following the 35 days of resting in the two- and three-layer sand bioreactor, and operation could be extended without clogging in the subsequent second runs. Thus rest periods could be used to recover treatment performance of sand bioreactors. Resting of drained sand bioreactors improved the treatment performance and lengthened the bioreactor runs. A rest period for 35 days was sufficient to recover the sand bioreactor performance. Reclamation of top layer of the sand bioreactor, such as plowing and raking, is recommended to improve the restoration effect because natural ventilation of the sand bioreactor is required during and after the rest period. Periodic operation of sand bioreactors would also be beneficial. Periodical turnover of the 1- or 2-in. top layer of pea gravel is recommended because it will improve aeration and disperse the accumulated fat.