Textile Dye Removal from Wastewater by Biological Methods: A Review

About 10,000 different types of dyes are available, and the annual global production of dyes is above 7 × 105 metric tons. They are mainly used for textile, paper, food, and pharmaceutical industries. The textile industry is the largest dye consumer in the worldwide heeding about 50% of dye usage. As reported, a massive amount of textile dyes is released with wastewater from the textile dying industry and is considered as one of the serious environmental problems in the world. The decolorization, foul smell, and contamination of waterbodies are the major problems related to waste textile dyes, and certain dyes are reported as toxic and carcinogenic. Most of the dye compounds are stable and difficult to degrade. Numerous techniques like physical, chemical, biological, and combined methods have been developed for eliminating textile dyes in wastewater. This paper presents a review of literature on biological dye removal techniques (aerobic, anaerobic, and facultative) their merits and demerits to improve the resilience of the ecosystems. Other than that, biological methods generate fewer harmful by-products. Biological dye removing methods lead to less environmental impacts with reduced toxicity and carcinogenic risks standing out as a safe and effective solution. This review consolidates the available information on diverse treatment methods for industries to select appropriate treatment methods for their dye-contaminated effluents.