Bioremediation of polluted Kalyani river water using immobilized microbial consortia
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Date
2021-10
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The pollution of rivers and other water bodies has become one of major concern for the entire world especially for the developing nations like India. The effluents of various industries, loaded with synthetic dyes in large amount, are great threat for the ecosystem and their native flora and fauna. Therefore, the present investigation was carried out for the bioremediation of several toxic industrial azo dyes (Congo red, Direct brown and Diazo black) and wastewater from Kalyani river, Rudrapur, Uttarakhand, using eighteen microbial cultures (fungi, microalgae and cyanobacteria). All the microbial cultures were initially screened for their in-vitro dye decolorization efficiencies. Then, the selected isolates were further evaluated spectrophotometrically for the quantification of dye decolorization for all three azo dyes. Five fungal cultures, (WRTP2, WRTP3, WRTP4, BS1 and WRFP1) were able to decolorize all the three azo dyes in 1-4d. The microbial consortia were developed using the potential microbial monocultures (fungi, microalgae and cyanobacteria) to increase the extent of dye removal for the three azo dyes (Congo red, Direct brown and Diazo black). The consortia were more efficient and showed complete decolorization of the liquid cultures in lesser time (within 48h). The effect of dye concentration and pH of the medium were also found to have significant impact and the developed microbial consortia (WRTP3+Syn) and (BS1+ Syn) were able to grow and decolorize the azo dyes (Congo red and Direct brown) upto a conc. of 1200 mgL-1. The immobilized co-cultures (on stainless steel sponge and cotton plugs) showed rapid decolorization of dye direct brown and were able to decolorize 100 mgL-1 and 200 mgL-1 of dye in 14h and 20h respectively. The extent of dye decolorization during microbial decolorization process was monitored by UV-visible spectroscopy, FT-IR and SEM analysis. The Kalyani river water was analysed for its physio-chemical parameters. Reduction in the values of BOD, COD, electrical conductivity, pH, colour and turbidity in the microbially treated wastewater sample was also recorded.