Reuse of wastewater in yarn dyeing processes

In the textile dyeing industry where water consumption is high, the aim is to reduce carbon and water footprint by treating wastewater with appropriate recovery methods and using it in new dyeings. The textile dyeing industry is widespread in our country and water consumption is high. Therefore, reusing wastewater for certain types of yarn will significantly reduce water consumption. The dyeing of products in textile dyeing factories can consist of 3-15 baths depending on the dyeing process, and clean water is used in all of these baths. Therefore, wastewater is generated at every stage. These wastewaters are sent to the wastewater pool to not be reused. When the dyeing processes of different yarn types such as viscose, cotton, acrylic, polyester, and nylon are examined, they are dyed with different numbers of baths. In addition, the dye ratios of the given dyeing agents are different from each other. For example, when the water remaining in the bath is examined after dyeing acrylic, clear water is seen, while the situation is the opposite for viscose/cotton. At this stage, wastewater samples generated in each dyeing process can be analyzed with appropriate methods and reused for dyeing certain yarn types. By applying treatment processes according to the content of wastewater, British Textile Technology Group and Goodman and Porter textile wastewater reuse criteria can be met or wastewater that has been treated at a maximum level can be integrated into the dyeing process or post-dyeing washing baths with nearly 100% performance. It is estimated that 20% of the world's clean water resources are used in the textile industry and up to 100 liters of water are required to produce one kilogram of textile product. In this direction, by applying environmentally friendly methods to reduce high water consumption in textile dyeing factories and aiming to reuse wastewater, the daily water consumption in textile dyeing factories is aimed to be minimized. In this thesis, research has been conducted on acrylic (cationic dyeing) and cotton (reactive dyeing), which are relatively easier to dye than other fiber types. For a facility with a daily water consumption of 100 tons, the aim is to discharge 30% of the water to the recycling pool and to use all of the discharged water again in dyeing processes. Key Words: Climate Change, Textile Dyeing, Waste Water, Recycling, Carbon Footprint