title: Aromatic amine degradation in a UASB/CSTR sequential system treating Congo Red dye.
abstract: In this study an anaerobic (upflow anaerobic sludge blanket reactor)/aerobic (completely stirred tank reactor) sequential system was used to treat a synthetic wastewater with minerals and co-substrate together with 100-4000 mg L(-1) of Congo Red dye (Direct red 28) (CR), which is a banned azo dye in Turkey. The effect of hydraulic retention time (HRT) on the decolorization and the COD removal efficiency was investigated at constant 100 mg L(-1) Congo Red concentration. 77% of COD and 95% of color was removed at a HRT of 0.486 days and a maximum organic loading rate of 6.656 kg COD m(-3) day(-1) in the anaerobic/aerobic stage. In the continuous operations, 88% of COD, 99% of color and 91% of total aromatic amine (TAA) were removed at a HRT of 3.60 days and at a CR concentration of 4000 mg L(-1). This corresponds to an organic loading rate of 1.81 kg COD m(-3) day(-1), and a CR dye loading rate of 46.37 g dye m(-3) h(-1), respectively, in the whole system. The TAA produced under anaerobic conditions was ultimately removed in the aerobic stage, resulting in very low aromatic amine recoveries (5-18%) in the last one. Therefore the aerobic effluents exhibited higher IC50 and specific methanogenic activities (SMA) compared to anaerobic and dye containing samples, indicating the reduced toxicity.
authors.affiliation: Department of Environmental Engineering, Engineering Faculty, Dokuz Eylul University, Buca Kaynaklar Campus, Izmir, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Işik
authors.forename: Delia Teresa
authors.initials: DT
authors.lastname: Sponza
mesh_terms: D000588:Amines / Q000378:metabolism*; D001420:Bacteria, Aerobic / Q000502:physiology; D001421:Bacteria, Anaerobic / Q000502:physiology; D019149:Bioreactors; D004396:Coloring Agents / Q000378:metabolism*; D003224:Congo Red / Q000378:metabolism*; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D000588:Amines; D004396:Coloring Agents; D003224:Congo Red