Integrated bio-chemo degradation of Mordant Yellow 10 using upflow anaerobic packed bed reactor (UAPBR) and tray type photo-Fenton reactor (TPFR)

Abstract

Feasibility of the two stage anaerobic/photo-Fenton process to mineralize a mono-azo dye, Mordant Yellow 10 (MY10) in continuous mode of operation was demonstrated using an upflow anaerobic packed bed reactor (UAPBR) and a novelly-designed tray type photo-Fenton reactor (TPFR). The halotolerant Pseudomonas aeroginosa BRPO3 strain used in the UAPBR system demonstrated stable dye decolorization with almost 99% of dye removal efficiency up to 220 mg/L of dye concentration supported by glucose as co-substrate operated at 24 h retention time. Maximum dye removal rate was observed to be 933 ± 8 mg/day at 200 mg/L of dye concentration. The amines formed in the UAPBR were degraded almost completely (99%) using hydrogen peroxide (340 mM) in TPFR packed with iron shavings as the catalyst. Ecogenotoxicity studies with earthworm Eisenia fetida using alkaline comet assay revealed that the untreated and bio-treated dye water induced DNA damage in coelomocytes of earthworm whereas sequentially treated solution did not induce damage even after 72 h of exposure. This is probably the first study to investigate the detoxification efficiency of sequential treatment systems operated in continuous mode.