Treating technologies for dyeing wastewater and synergistic green low-carbon strategies: A comprehensive review from efficient decolorization to resource recovery systems

The textile dyeing industry, as a significant industrial sector in China, discharges 2-23 billion tons of wastewater annually, accounting for 11% of total industrial wastewater. This wastewater is characterized by complex composition, deep color, poor biodegradability, and high salinity, making treatment highly challenging. Despite policy requirements stipulating a 60% wastewater reuse rate, the actual rate remains below 7%, highlighting an urgent need to overcome technological bottlenecks. This review systematically summarizes and critically evaluates recent advances in dyeing wastewater treatment, with a particular focus on the integration of physicochemical and biological processes for synergistic pollutant removal and resource recovery. In contrast to existing reviews, this work provides a holistic analysis of the mechanisms, efficiencies, and limitations of various technologies under realistic conditions, and proposes a novel framework aimed at achieving "efficient decolorization – low-carbon desalination-resource recovery". • Systematically reviews dyeing wastewater treatment technologies from physicochemical to biological methods • Proposes an integrated framework for “efficient decolorization - low-carbon desalination – resource recovery” • Analyzes the synergistic effects and mechanistic complementarity of hybrid physicochemical-biological processes under realistic conditions • Evaluates limitations and applicability of various technologies, emphasizing biodegradation and green material use • Identifies future directions including smart water management, AI integration, and circular economy strategies