Akademik Veri Yönetim Sistemi
Fresenius Environmental Bulletin, cilt.13, ss.1493-1499, 2004 (SCI-Expanded)
In this study the anaerobic treatability of p-nitrophenol was investigated in an anaerobic/aerobic sequential reactor system. The studies were carried out in continuous mode and the effluent of the anaerobic migrating blanket reactor (AMBR) was used as feed for the aerobic completely stirred tank reactor (CSTR). The stainless steel-AMBR had a 13.5 L effective volume. The CSTR consisted of an aeration tank (effective volume = 9 L) and a settling compartment (effective volume = 1.32 L). Since the IC50 value of p-nitrophenol (p-NP) was found to be 26.5 mg L-1 (anaerobic toxicity tests), the AMBR was started with a p-NP concentration of 10 mg L-1, which was increased to 40 mg L-1 during continuous reactor operation. The COD, p-NP and p-aminophenol values were monitored in the effluent and compartments of the AMBR. Furthermore; the COD and p-NP removal efficiences, NO2-N, NO3-N, and NH4-N were determined in the aerobic CSTR. COD and p-NP removal efficiencies were 93 % and 94 % in AMBR, and 73 % and 52 % in CSTR at a loading rate of 3.85 g p-NP m-3 day-1. The maximum methane production rate and percentage were approximately 1000 ml day-1 and 50 % at this loading rate, respectively. The ratio of total volatile fatty acids (TVFA)/bicarbonate alkalinity (BA) showing the anaerobic reactor stability was lower than 0.4 and p-NP was transformed to p-aminophenol (p-AP) in the anaerobic phase. Mineralization of p-AP and phenol was determined in the oxidative CSTR stage. The total p-NP and COD removal efficiencies were averaged to be 97 % and 98 % in the used (anaerobic /aerobic) sequential reactor system at a loading rate of 3.85 g p-NP m-3 day-1.