Effect of Increasing Nitrobenzene Loading Rates on the Performance of AMBR and Sequential AMBR/CSTR Reactor System

Abstract

A laboratory scale sequential anaerobic migrating blanket reactor (AMBR)/aerobic completely stirred tank reactor (CSTR) system was operated to investigate the effect of increasing nitrobenzene (NB) concentrations on the performance of AMBR/CSTR reactor system. The reactor system was operated at increasing NB loading rates from 1.93 to 38.54 g NB m−3 day−1 and at a constant hydraulic retention time of 10.38 days . In this study, chemical oxygen demand (COD) and NB removal efficiencies, variations of bicarbonate alkalinity (Bic.Alk.), total volatile fatty acid (TVFA), and total methane gases were monitored. COD removal efficiencies were 93–94% until a NB loading rate of 5.78 g m−3 day−1 in the AMBR reactor. For maximum COD removal, the optimum NB loading rate and NB concentration were found to be 5.78 g m−3 day−1 and 60 mg L−1 , respectively. COD removal efficiencies decreased from 94 to 87% and to 85% at NB loading rates of 1.93–28.90 and 38.54 g m−3 day−1 , respectively. COD was mainly removed in the firs...