G-Journal of Environmental Science and Technology (Apr 2020)
Biodegradation of textile dye effluent through Indigenous bacteria
Abstract
The textile industry is considered as one of the major generators of toxic chemical wastewater in India. Dyes released by the textile industries pose a threat to environmental safety. Dye decolorization through biological means has gained momentum as these are cheap and can be applied to a wide range of dyes. The present study concentrates in the isolation, identification of indigenous bacteria namely D1, D2, D3 and D4 from textile dye effluent collected from the local textile dyeing shop located at Gurahakuan, Banda district, Uttar Pradesh, India, and evaluation of their ability to decolorize dyes sample. The isolated bacteria were identified through morphological and biochemical characteristics. Scanning electron microscope (SEM) analysis of isolated bacteria showed that all the bacteria appeared rod-shaped with size ranging from 1.33 to 2.84 µm. The physico-chemical analysis of dye effluent indicated the bluish-black color of the effluent having pH of about 8. The Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) value of the raw sample was estimated to be 470 mg/l and 800 mg/l, respectively, for dye effluent sample. The value of Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) was estimated to be 1760 mg/l and 560 mg/l, respectively, in our dye effluent sample. The study aims to isolate and optimize four bacterial isolates having the ability to degrade and decolorize azo dyes produced in the final dying effluent. The optimization results revealed that all the bacteria showed maximum growth at pH 8, temperature 35°C and declines further. All the isolated bacterial species showed significant potential for dye decolorization and degradation at varying wavelengths such as 420, 480, 506, 520, 620 and 668 nm but maximum removal of color (about 88%) was obtained at 668 nm after 48h by bacterial isolate D3. Thus, these selected native bacteria can be employed as a vital biological tool for developing decentralized wastewater treatment systems for decolorization of dye effluents through biosorption or biodegradation which is a cost-effective process.
