The Hong Kong Research Institute of Textiles and Apparel (HKRITA) has collaborated with the H&M Foundation to recycle blended textiles into high-quality fabrics and yarns.
Focusing on denim, HKRITA is launching two pioneering projects aimed at recycling indigo-dyed fabrics. The first project introduces an AI-driven mechanical recycling system that extracts reusable indigo-dyed warp yarns from denim without the use of chemicals or water.
This groundbreaking method addresses the challenges of recycling blended denim fabrics, which often suffer from quality degradation and lower recycling efficiency. The system mechanically extracts warp yarns—typically made from higher-quality dyed cotton—while an AI system identifies fabric structures and measures warp yarn density and denim orientation, achieving over 90 percent efficiency.
By recycling indigo-dyed yarns, denim manufacturers can significantly reduce their dependence on virgin cotton, thereby conserving resources like water and agricultural inputs. The extracted yarns are of high enough quality to be reused without additional dyeing, lowering both operational costs and environmental impact. This innovative project earned a gold medal at the International Exhibition of Inventions in Geneva.
HKRITA’s second project tackles denim wastewater pollution by using a biodegradable mechanism to remove indigo dye from wastewater. This method employs sunlight and macroalgae species such as Cladophora and Chaetomorpha, which metabolise and break down the dye, effectively decoloring the wastewater. The algae-based system can be integrated into denim factory operations, consuming carbon dioxide waste and providing an eco-friendly, energy-efficient solution to wastewater treatment.
Both projects have garnered interest from denim manufacturers in China and Southeast Asia. However, the main challenge lies in scaling these innovations to industrial levels, particularly in terms of engineering design for light penetration, water circulation, and macroalgae containment. Committed to overcoming these hurdles, HKRITA aims to integrate these new technologies into manufacturing processes to drive sustainable innovation.
