Assessing environmental impact of textile production with water alkalization footprint

The dyeing process contributes most to the water consumption and wastewater emission associated with the textile industry, leading to water depletion and degradation. The water footprint is an effective concept for evaluating the environmental impact of textile production processes on water bodies, and serves as a reference for practitioners seeking to develop suitable water management strategies. Water degradation can be quantified in terms of several sub-indicators, such as aquatic eutrophication, acidification, and ecotoxicity. However, some processes (such as the production of viscose fiber and dyeing) produce significant quantities of alkaline wastewater that can alkalize the receiving water bodies. In this study, we proposed the concept of water alkalization footprint to assess the potential impact of water alkalization caused by textile production. To achieve this, we constructed an evaluation framework and calculated the relevant characterization factors by considering the mechanisms of chemical reaction. A dyeing mill was selected as a case study to demonstrate the feasibility of the concept. The results indicate that the dyeing of 1 ton of viscose fabric produces a water alkalization footprint of 15.478 kg OH^- equiv, and that NaOH in the wastewater from the desizing and dyeing phases was the largest contributor at 97.23%.