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African Journal of Biotechnology

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Influence of recirculation rate on the performance of a combined anaerobic-aerobic reactor applied to the removal of carbon and nitrogen from poultry slaughterhouse wastewater

Carla L Lopes, Adriana N. de Lima Model, Jackeline T. Gotardo, Fernando H. Passig, Eloy L. de Mello, Benedito M. Gomes, Simone D. Gomes

Abstract


The objective of this study was to evaluate a combined anaerobic-aerobic upflow fixed-bed reactor with liquid phase recirculation for the removal of nitrogen and organic matter from poultry slaughterhouse wastewater. The reactor performance was evaluated with a hydraulic retention time (HRT) of 11 h and three different recirculation rates (R=0.5; 1 and 2). The highest nitrogen removal efficiency value was obtained with an HRT of 11 h (6.8 h in the anaerobic zone and 4.2 h in the aerobic zone) and a recirculation rate of 2. In this condition, the total nitrogen removal efficiency was 69%,  with effluent concentrations of 6 mg NH4+ L-1 and 12 mg NO3- L-1. For all tested conditions, there was good chemical oxygen demand (COD) removal, with efficiency above 95%. The effect of dilution and the favoring of mass transfer caused by the increase in the recirculation rate positively influenced reactor performance.


Key words: Anaerobic degradation, nitrification, denitrification, combined reactor.




http://dx.doi.org/10.5897/AJB2016.15578
AJOL African Journals Online