title: Effects of nitrobenzene concentration and hydraulic retention time on the treatment of nitrobenzene in sequential anaerobic baffled reactor (ABR)/continuously stirred tank reactor (CSTR) system.
abstract: The effects of increasing nitrobenzene (NB) concentrations and hydraulic retention times (HRT) on the treatment of NB were investigated in a sequential anaerobic baffled reactor (ABR)/aerobic completely stirred tank reactor (CSTR) system. In the first step of the study, the maximum COD removal efficiencies were found as 88% and 92% at NB concentrations varying between 30 mg L(-1) and 210 mg L(-1) in ABR. The minimum COD removal efficiency was 79% at a NB concentration of 700 mg L(-1). The removal efficiency of NB was nearly 100% for all NB concentrations in the ABR reactor. The methane gas production and the methane gas percentage remained stable (1500 mL day(-1) and 48-50%, respectively) as the NB concentration was increased from 30 to 210 mg L(-1). In the second step of the study it was found that as the HRT decreased from 10.38 days to 2.5 days the COD removal efficiencies decreased slightly from 94% to 92% in the ABR. For maximum COD and NB removal efficiencies the optimum HRT was found as 2.5 days in the ABR. The total COD removal efficiency was 95% in sequential anaerobic (ABR)/aerobic (CSTR) reactor system at a minimum HRT of 1 day. When the HRT was decreased from 10.38 days to 1 day, the methane percentage decreased from 42% to 29% in an ABR reactor treating 100 mg L(-1) NB. Nitrobenzene was reduced to aniline under anaerobic conditions while aniline was mineralized to catechol with meta cleavage under aerobic conditions.
authors.affiliation: Department of Environmental Engineering, Engineering and Architecture Faculty, Süleyman Demirel University, Isparta, Turkey.
authors.forename: Ozlem Selcuk
authors.initials: OS
authors.lastname: Kuscu
authors.forename: Delia Teresa
authors.initials: DT
authors.lastname: Sponza
mesh_terms: D000693:Anaerobiosis / Q000187:drug effects; D000814:Aniline Compounds / Q000302:isolation & purification; D001673:Biodegradation, Environmental / Q000187:drug effects; D019149:Bioreactors; D005740:Gases; D008697:Methane / Q000378:metabolism; D009578:Nitrobenzenes / Q000302:isolation & purification* / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D010100:Oxygen / Q000302:isolation & purification; D013997:Time Factors
chemical_list: D000814:Aniline Compounds; D005740:Gases; D009578:Nitrobenzenes; C036077:nitrobenzene; D008697:Methane; D010100:Oxygen; C023650:aniline