HKRITA innovates sustainable denim recycling

The Hong Kong Research Institute of Textiles and Apparel (HKRITA) is turning its attention to indigo with two innovative projects. The first is an AI-driven mechanical recycling system designed to extract reusable indigo-dyed warp yarns from denim fabrics. This chemical-free and waterless approach is the first of its kind, addressing the challenges of recycling denim blended with other materials. The system allows for their reuse in new denim production without the need for additional dyeing.

The process results in an impressive 90 percent efficiency in separating warp yarns, which are typically made from high-quality dyed cotton. The innovation reduces the need for virgin cotton and the environmental impact associated with dyeing denim, while also cutting costs on dyeing and wastewater treatment.

HKRITA’s second project explores a biodegradable mechanism to remove indigo dye from wastewater using sunlight and macroalgae species like Cladophora and Chaetomorpha. This algae-based system degrades the dye and consumes carbon dioxide emitted from denim factories, offering a cost-effective, energy-efficient, and eco-friendly solution to reducing dye pollutants in wastewater.

The main challenges lie in scaling these systems for industrial use. For the wastewater treatment project, scaling involves adapting the design for light penetration, water circulation, and macroalgae containment. Similarly, the mechanical warp-weft separation system needs to be scaled up to meet industrial production efficiency.