New Delhi, Aug 8 : A team of researchers from IIT Delhi has developed a new method to recycle denim waste to knitted garments without compromising quality.

The findings will also help reduce textile waste -- the discarded textiles and clothing after their use -- which end up in landfills.

India accumulates around 3.9 million tonnes of domestic post-consumer textile waste annually, of which only 4 per cent is recycled.

Those recycled lose fibre strength and face variability in colour and quality.

However, with the novel method, the IIT researchers found that up to 50 per cent of recycled yarns can be used in knitted clothing without deteriorating the feel of the product.

"To reduce the roughness of recycled yarns, a softening treatment was applied to the fabric, which ensured that the tactile feel of the final product is the same as that of virgin products, said Prof Abhijit Majumdar, Dept. of Textiles and Fibre Engineering, IIT Delhi.

"We have demonstrated our work with denim waste, and it can be extended with any other textile waste," he added.

In the study, detailed in the Journal of Cleaner Production, the team recycled waste denim into yarns, ensuring minimum damage to the fibre properties by optimising the process conditions.

Recycled yarns were then blended into knitted fabric using the seamless whole garment technology. Knitted garments were produced, varying the recycled yarn content from 25 per cent to 75 per cent.

Another key aspect of this research was to quantify the environmental benefits through life cycle assessment (LCA) in the Indian context.

Analysis by the IIT Delhi team showed that around 30-40 per cent of environmental impacts can be mitigated in terms of greenhouse gas emission, acid rain, and fossil fuel depletion, whereas for ozone layer depletion, it is around 60 per cent.

As the use of recycled fibres could reduce the use of virgin cotton, the pesticides, fertilisers and water used for cultivation can also be saved.

Among the processes involved, the cotton cultivation stage itself contributes 24 per cent to global warming, making the virgin yarns less environment-friendly.

"The research team is now exploring the possibility of recycling textile waste materials multiple times," added Prof B.S. Butola, Dept. of Textile and Fibre Engineering, IIT Delhi.

/IANS