Biodecoloration of textile dye effluents

Worldwide, about 7x105 tonnes of dyes with a wide range of chemical structures are produced annually. Canada releases about 500 tonnes per year to the environment with the majority of plants in Ontario and Quebec. Even though effluents may contain <1 ppm, the color imparted to receiving waters has a highly undesirable appearance. As a visible pollutant, there is public pressure to treat these waste streams. Traditionally, these effluents have been treated with municipal wastewaters where dye degradation has been poor. Physical and chemical techniques are only effective for certain dyes, may generate large volumes of sludge or may be expensive. Hence, there is an increasing need to develop new color removal technologies such as biological treatment that are less expensive and easy to use.

Thiru's demonstration

White rot fungi use lignin-degrading enzymes to degrade organic compounds such as polyaromatic hydrocarbons, chlorophenols, polychlorinated biphenyls, and dyes. Immobilized cultures tend to have higher activity and are more resilient to environmental changes such as pH, or exposure to toxic chemical concentrations than suspension culture. The objective of this research is to develop a cost-effective, biological process using immobilized white rot fungi to decolorize textile mill effluents. This can be achieved by choosing an appropriate immobilization technique, bioreactor design and operating conditions to optimize decoloration at the lowest cost.

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