An overview of biological mechanisms and strategies for treating wastewater from printing and dyeing processes

To create beautiful fabrics, the printing and dyeing industry uses dyes, dyeing additives, and other substances. Dyes include anthraquinone dyes, azo dyes, etc. These dyes are usually difficult to degrade, and low concentrations of dye will reduce the transparency of the water. The printing and dyeing industries produce enormous amounts of wastewater, which together account for 11% of China's annual wastewater emissions, or 2–2.3 billion tons. The environment and creatures will suffer serious consequences if the wastewater from printing and dyeing is not cleaned. Biological methods for wastewater treatment are cost-effective and environmentally beneficial. The primary objective of the biological technique is to eliminate pollutants via biological metabolic processes such as biodegradation, bioadsorption, and bioaccumulation. Biological treatment of wastewater can also produce high-value by-products, such as biofuels, bio-feed, biochar, etc. In this work, which focused on the mechanisms, biological techniques for the treatment of printing and dyeing wastewater are carefully evaluated. Furthermore, challenges and future development trend of biological method in the treatment of printing and dyeing wastewater were analyzed. This review will promote the development of biological methods to treat printing and dyeing wastewater.