Process based assessment of wastewater quality and rinse water reuse potential in denim finishing: a scalable framework for circular water management

Industrial textile production is a significant contributor to freshwater pollution, particularly in water-intensive processes such as denim finishing. This study presents a process-based assessment of wastewater quality and rinse-water reuse potential using a stage-specific Water Quality Index (WQI) framework. By analyzing effluents from six major denim finishing stages, critical pollution hotspots were identified, and the feasibility of cascading rinse-water recovery was evaluated. Results demonstrate that WQI values decreased significantly after rinsing, with reductions reaching up to approximately 70% depending on the process stage. Furthermore, the proposed stepwise reuse strategy has the potential to reduce freshwater consumption by nearly two-thirds while maintaining operational performance. Beyond a site-specific application, the proposed methodology offers a transferable framework for industrial water optimization and circular water management in textile facilities globally. The findings contribute to advancing sustainable industrial practices and support progress toward SDG 6 and SDG 12.