Removal and degradation of dyes from textile industry wastewater: Benchmarking recent advancements, toxicity assessment and cost analysis of treatment processes

Clean and safe drinking water is vital. Tragically, this quality has been degraded due to the anthropomorphic and continuous discharge of toxic and non-biodegradable organic pollutants into the aquatic environment. Among the many sources of water pollution, the textile industry has become a major problem as wastewater containing dyes is often discharged into natural water bodies. Studies have shown that a major portion (∼20 %) of dyes is lost during synthesis and processing operations and end up in wastewater. Due to their ubiquitous industrial use, textile dyes are categorized as pollutants of major concern, posing an ongoing threat worldwide. The discharge of dyes and/or their degradation byproducts in the aquatic environment poses serious health risks to aquatic plants, organisms, and humans, making it necessary to remove them at their source. This review article aims to present and discuss the most advanced and state-of-art technical and scientific developments in the removal and degradation of dyes from textile wastewater. This review discusses the emergence of the latest nanomaterials, current focus, and superior efficiencies of the state-of-the-art materials, with emphasis on physical and chemical approaches. By comparing frequently studied treatment methods for cost and efficiency, the future outlook provides insights into selection of treatment options, knowledge gaps, and how to improve the efficiency of applicable systems. This feasibility analysis will help readers select the most efficient treatment process from both a performance and financial perspective. While multistage hybrid technologies are worth pursuing, few technologies such as ozonation and photo-Fenton have emerged as promising independent processes. Their individual combination with filtration methods has the ability to provide an economically feasible and time-efficient solution. However, there is room for further improvement in developing or tailoring models, methods and processes that target not only dyes but also secondary factors (such as chemical oxygen demand), while remaining cost-effective and affordable for all parts of the world.