Bioremediation of Industrial Wastewater

Abstract

Reactive dyes containing diazo bonds are more resistant to anaerobic reduction in comparison to monoazo dyes. Reactive Yellow-145 (RY-145) which is used as a model dye is a diazo dye having -SO3H group in its structure. A novel bacterial consortium was isolated from the soil samples of a local dye manufacturing unit at Ahmedabad, Gujarat, India. This culture was used for decolorization parametric study of RY-145 under various operating conditions. The consortium was successfully able to decol- orize, 300 mg l-1 of selected dye up to 97% within 11 h under static facultative conditions at pH 7.0 and 37 C temperature. Static facultative condition was found to be superior for complete and faster decolorization of RY-145 as compared to shak- ing aerobic condition. The decolorization process approximates rst order kinetics for concentration up to 200 mg l-1 and later up to 600 mg l-1 approximates zero order kinetics with respect to initial dye concentration. Optimum nutrient broth concen- tration, inoculum size and tolerable salt concentration were found out to be N (13 mg l-1), 10% (v/v) and 4% (w/v) respectively without compromise on decolorization rate. The UV - Visible Spectroscopic analysis results indicate the decolorization of dye. The HPLC and FTIR results con rm degradation of RY-145 into smaller com- pounds. For the commercial viability, combination of specially prepared synthetic medium and extract of agriculture waste is used as a growth medium for consor- tium in place of nutrient broth. COD reduction of nearly 70% is achieved for 20 times diluted industrial wastewater. Specially designed continuous column reactor (PMSCCR) has also been used for batch and continuous study of decolorization of RY-145. To the best of our knowledge no reports exist in the open literature for the decolorization and biodegradation of RY-145 using bacterial consortium.