Microbial decolorization of reactive black-5 in a two-stage anaerobic-aerobic reactor using acclimatized activated textile sludge.
A two-stage anaerobic-aerobic treatment process based on mixed culture of bacteria isolated from textile dye effluent was used to degrade reactive black 5 dye (RB-5). The anaerobic step was studied in more detail by varying the dye concentration from 100 to 3000 mg l(-1). The results showed that major decolorization was achieved during the anaerobic process. The time required for decolorization by > 90% increased as the concentration of the dye increased. It was also found that maintaining dissolved oxygen (DO) concentration below 0.5 mg l(-1 )and addition of a co-substrate viz., glucose, facilitates anaerobic decolorization reaction remarkably. An attempt was made to identify the metabolites formed in anaerobic process by using high performance liquid chromatography (HPLC) and UV-VIS spectrophotometry. A plate assay was performed for the detection of dominant decolorizing bacteria. Only a few bacterial colonies with high clearing zones (decolorization zones) were found. The results showed that under anaerobic condition RB-5 molecules were reduced and aromatic amines were generated. The aromatic amine metabolite was partly removed in subsequent aerobic bio-treatment. It was possible to achieve more than 90% decolorization and approximately 46% reduction in amine metabolite concentration through two-stage anaerobic-aerobic treatment after a reaction period of 2 days.
Mohanty
Sagarika
S
National Environmental Engineering Research Institute, Nehru Marg, 440020, Nagpur, India.
Dafale
Nishant
N
Rao
Nageswara Neti
NN
D000332:Aerobiosis; D000588:Amines / Q000032:analysis; D000693:Anaerobiosis; D001420:Bacteria, Aerobic / Q000378:metabolism; D001421:Bacteria, Anaerobic / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000378:metabolism*; D009282:Naphthalenesulfonates / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013056:Spectrophotometry, Ultraviolet; D013784:Textiles; D018508:Water Purification / Q000379:methods*
D000588:Amines; D004396:Coloring Agents; D009282:Naphthalenesulfonates; D012722:Sewage; C063421:Remazol black B; D010100:Oxygen