Environmental assessment of a pilot-scale water recycling system for denim production

On-site treatment and recycling of denim wastewater represent an important opportunity to advance resource efficiency and reduce environmental burden of textile production. Because emerging treatment technologies can shift impact across the value chain, their evaluation requires a comprehensive life-cycle perspective. This study applies life cycle assessment to a pilot-scale water recycling system developed for denim manufacturing, integrating advanced oxidation processes, membrane treatment and photovoltaic-powered operation. Using data from the technology developers and modelled baseline scenarios, several optimisation pathways were explored. Results show that, relative to conventional wastewater treatment systems, the recycling system achieves lower impacts in water use and freshwater ecotoxicity categories by factors 5 and 50 respectively when recovering brine and operating solely on solar-derived electricity. Key contributing processes to the other assessed impacts are the consumption of chemicals during the operation stage and the manufacture of photovoltaic and battery components. The use of recyclable materials in energy components enhances overall system performance, allowing the system to counteract its impact on climate change and on nearly all the remaining impact categories. The findings highlight the importance of integrating resource recovery, renewable energy, and design-for-recycling principles to maximise the sustainability benefits of decentralised industrial water recycling systems.