New Delhi, Sep 16 (PTI): Researchers at Indian Institute of Technology (IIT) in Guwahati and BHU have developed an eco-friendly biological approach to treat textile wastewater containing toxic azo dyes, officials said on Wednesday.
The findings of the research have been published in Environmental Geochemistry and Health, a peer-reviewed, cross-disciplinary journal that publishes innovative research linking health and the environment.
According to Selvaraju Narayanasamy, Associate Professor, Biochemical and Environmental Engineering Laboratory, the research provides a scientific foundation to develop biological treatment systems for textile wastewater containing azo dyes. The approach could offer an eco-friendly alternative or complementary treatment to conventional chemical and physicochemical methods.
The research demonstrates the ability of a novel bacterium called 'Brevundimonas sp. AJZ05' to degrade 98.50 per cent of Direct Blue-6 (DB-6), a widely used synthetic dye, while producing degradation products that were found to be non-toxic after bacterial treatment.
"Textile wastewater can contain azo dyes that are difficult to remove because of their stable chemical structure. These dyes contain an azo bond (–N=N–), which contributes to their colour and chemical stability, making them resistant to conventional treatment processes. Untreated textile effluents can pose risks to aquatic ecosystems and may have implications for human health," Narayanasamy said.
Conventional chemical and physicochemical treatment methods can also be energy-intensive and may generate secondary pollutants. Importantly, simply removing the visible colour from wastewater does not necessarily eliminate the underlying toxicity.
To address this challenge, the researchers isolated Brevundimonas sp. AJZ05 from a native textile effluent discharge site. The bacterium was found to produce azoreductase, an enzyme capable of attacking the azo bond that gives dyes their characteristic colour and stability.
"Using a statistical multi-objective optimisation approach based on Response Surface Methodology, we simultaneously optimised dye degradation and azoreductase production. A key feature of the study is that we went beyond measuring colour removal. Our research team analysed the metabolites formed during the biodegradation process and assessed their toxicity," Narayanasamy said.
"The degradation products were found to be non-toxic after bacterial treatment, indicating that the process can potentially transform the dye into safer compounds rather than only making contaminated water appear visually cleaner. Through this research, we have demonstrated a promising biological route towards safer and more sustainable wastewater treatment," he added.
Narayansamy explained that the team is now working towards translating the laboratory-scale findings into a practical and scalable wastewater treatment technology. "We plan to develop a continuous treatment system for azo-dye removal from textile wastewater, with the long-term goal of advancing the microbial platform towards industrial application," he said.
(PTI)
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