Environmental hazard in textile dyeing wastewater from local textile industry

Colorants and chemicals used in the textile coloration process are required to meet the fashion demands; however these introduced serious environmental hazards that are mainly resulted in effluent loading, containing the toxic, carcinogenic, and mutagenic substances, to natural environment. Textile dyeing process and the rinsing of dyed fabric utilize a variety of substances including dyes/ pigment, fixing agent, surfactants, leveling agent, mordant, salts etc. However, all these substances are not fully consumed in the process, and a residual content remains in the dyeing effluent. This review observes the challenges to environment posed by the dyes and chemicals present in spent dye bath, progress in possible remedies in dyeing wastewater treatment including the nanotechnology; and particularly discusses the studies based on the dyeing effluent samples collected from the local textile processing industries. There are obvious case studies made in different regions, using the process wastewater from the local textile dyeing and processing industries, confirming the need for research and innovation to replace or control the hazardous dyes and chemicals in conventional dyeing process and making the resulting effluent more environment- friendly. Moreover, the cleaner production practices and environmental standards are introduced in improving the textile dyeing process. Selection of dyes and chemicals, use of best available techniques, and wastewater treatment technologies can significantly improve the textile dyeing to become an environment- friendly process.