Comparison of anaerobic baffled (ABR) and migrating blanket reactors (AMBR) in the anaerobic treatability of nitroorganic compounds

In the framework of this Ph. D. thesis, the treatability of p-nitrophenol (p-NP) and nitrobenzene (NB), which are toxic, inhibitory and biorefractory nitroorganic compounds were compared in an sequential Anaerobic Migrating Blanked Reactor (AMBR)/aerobic Continuously Stirred Tank Reactor (CSTR) and sequential Anaerobic Baffled Reactor (ABR)/aerobic Continuously Stirred Tank Reactor (CSTR) reactor systems at increasing p-NP and NB loading rates and six different HRTs. COD, p-NP and NB removal efficiencies, total gas, methane gas productions, methane percentage, TVFA, Bic.Alk., TVFA/Bic.Alk. ratios were investigated separately in AMBR and ABR reactors at increasing p-NP and NB loading rates and decreasing HRTs. Furthermore, appropriate substrate and biogas kinetic models were determined for AMBR and ABR reactors treating p-NP. High COD, p-NP and NB removal efficiencies were obtained at HRTs varied between 10.38 days and 3.5 days in AMBR and ABR reactors. Methane gas percentages were high between these HRTs. pH, TVFA, Bic.Alk. and TVFA/Bic.Alk. ratios were found between optimum values in AMBR and ABR reactors through continuous operation. Toxic p-NP and NB transformed to less toxic intermediate products in anaerobic/aerobic sequential reactor system. In this study, p-NP transformed to p-aminophenol under anaerobic conditions. NB transformed to aniline under anaerobic conditions, then aniline biodegraded to catechol under aerobic conditions. The appropriate substrate removal and biogas production kinetic models were found as Modified Stover Kincannon model for AMBR and ABR reactors treating p-NP. The results of this study showed that these reactors can be used effectively to treat the toxic wastewaters containing p-NP and NB. Keywords: Anaerobic migrating blanked reactor (AMBR), anaerobic baffled reactor (ABR), para-nitrophenol (p-NP), nitrobenzene (NB), anaerobic treatment, anaerobic/aerobic treatment, p-AP, aniline, toxicity.