Performance of p-nitrophenol (p-NP) fed sequential anaerobic migrating blanket reactor (AMBR)/aerobic completely stirred tank reactor (CSTR) system under increasing organic loading conditions

In this study the anaerobic treatability of p-nitrophenol (p-NP) was investigated in an anaerobic/aerobic sequential reactor system under increasing organic loadings during operation period of 186 days. Lab-scale anaerobic migrating blanket reactor (AMBR)/completely stirred tank reactor (CSTR) system consisted of effective volumes of 13.5 and 9 L, respectively. Synthetic wastewater was obtained from constant p-NP concentration of 40 mg/L and a glucose concentration giving 3000 mg/L COD as primary substrate. The studies were carried out in continuous mode and the effluent of the AMBR reactor was used as the feed for the CSTR reactor. The AMBR/CSTR reactor system was operated at organic loading rates (OLRs) increasing from 0.31 to 3.25 kg/m3 day. COD and p-NP removal efficiencies were decreased from 92% to 79% and from 94% to 86%, respectively, when the COD loading rates were increased from 0.31 to 3.25 kg/m3 day in AMBR. The total COD and p-NP removal efficiencies were 94% and 91% in whole (AMBR/CSTR) reactor system, at a COD loading rate of 3.25 kg/m3 day, respectively. The total gas and methane gas production increased with increased OLRs. The daily total and methane gas productions were 12.25 and 3.8 L/day at OLR of 3.25 kg/m3 day, respectively. Methane gas percentage was also found as 31% at this loading rate.