Integrated printing and dyeing wastewater treatment

The printing and dyeing industry is a typical high water consuming industry that consumes nearly 100 million tons of process softened water annually. The sources and pollutant components of printing and dyeing wastewater are very complex, with characteristics such as large changes in water quality, high organic content, and high chromaticity (mainly colored dyes). Direct discharge poses great harm to human health and the living environment, while also causing waste of water resources. With the increasing attention of the country and society to environmental protection requirements and the demand for sustainable development, traditional treatment methods have become increasingly difficult to meet the requirements of production and environmental protection.
Printing and dyeing wastewater mainly contains dyes, slurries, dyeing auxiliaries, fiber impurities, oil agents, acids, alkalis, and inorganic salts. The composition is complex and the discharge volume is large, with high chromaticity, alkalinity, high pH, and many difficult to degrade biological substances. It is widely recognized as one of the main harmful wastewater that is difficult to treat. The coagulation method for treating printing and dyeing wastewater has the advantages of good treatment effect and low cost, making it an important means of treating industrial wastewater.
Membrane separation technology is a new, efficient, and environmentally friendly separation technology. In recent years, with the continuous development and progress of membrane separation technology in China, modern high-tech membrane separation technologies (mainly ultrafiltration, nanofiltration, and reverse osmosis) have been widely and successfully applied in the printing and dyeing industry, and have produced good economic and social benefits, bringing new opportunities for technological innovation in the printing and dyeing industry.