A review on treatment technologies for printing and dyeing wastewater (PDW)

The scarcity of clean and fresh water in some parts of the world, which is exacerbated by man’s activities either through domestic or industrial use, has been an age-old cause of worry. Printing and dyeing wastewater is the aqueous effluent released by factories that operate the dyeing and finishing of wool and silk, among other things. The printing and dyeing wastewater (PDW) contains a high concentration of dyes, salts, and other contaminants. This study is a review of published literature that utilised various technologies for the treatment of PDW. The studied technologies include adsorption, membrane technology, advanced oxidation processes, and biological processes. The strengths as well as the drawbacks of these technologies were studied. It was observed that adsorption, membrane technology, and biological processes recorded a removal efficiency of ˃80%, a rejection rate of ˃90%, and an effective dye degradation rate of ˃96%, respectively. From the study, it was observed that advanced oxidation processes is the most viable technique for PDW treatment due to its simplicity, efficiency, scalability, and from the economic point of view. Future perspectives, such as product recovery from the PDW waste stream, modelling and optimisation of the printing and dyeing processes, and the adoption of zero liquid and waste discharge, were also presented in this study. Finally, PDW treatment technologies should strike a balance between being environmentally friendly, efficient, and cost-effective to achieve robust and sustainable wastewater treatment programs.