Physicochemical characterization and Bioremediation perspective of textile effluent, dyes and metals by indigenous Bacteria

Physicochemical and bacteriological status of a local textile mill effluent showed considerably high values of temperature (40 °C), pH (9.50), EC (3.57 μs/m), BOD (548 mg l−1), COD (1632 mg l−1), TSS (5496 mg l−1), TDS (2512 mg l−1), heavy metals ions (0.28-6.36 mg l−1) and color above the prescribed fresh water limits. However, a considerable decline in almost all pollution indicators from source to sink indicated signs of natural remediation. Ten bacteria strains isolated from effluent showed comparatively higher resistance (MRL) (mg l−1) (average) for 10 heavy metals than against four structurally different dyes tested on solid media of mineral salt. Overall bacterial resistance was quite high against Fe3+ (2820), Cr3+ (1203), Zn2+ (1122), Mn2+ (804) and Pb2+ (435), whereas, it varied amid 300-500 in four dyes. Bacterial decolorization/degradation of dyes indicated on solid media was confirmed through experiments carried out in liquid broth.