The cotton-based waste textiles such as used jeans to produce biogas and bioethanol. The cotton is composed of almost pure cellulose polymers. These polymers can be hydrolyzed to sugar. This sugar can be fermented to ethanol by baker’s yeast or digested to biogas (methane) by bacteria.

This process is principally simple. But, there are a lot of details that make it difficult and interesting subject for research. We have succeeded well to produce almost 0.5 kg ethanol or 380 liters methane from each kg cotton. However, we are still working with the challenges of the process and other types of textile materials in order to make the concept attractive for the industries.

This project is aimed to investigate recycling waste textiles to society in form of biogas and/or ethanol. The waste textiles compose 8-10 percent of the incoming waste to the station in Borås, Sobacken, with a volume of about 17 000 tons per year. This waste is now smashed and burned in the incinerators. However, due to technical difficulties, it is desired to find other methods in order to handle textile waste. In a previous project, carried out in collaboration with SP Swedish Technical research institute, Borås Energi & Miljö AB, Borås energy and environment Ltd. and Dalkia AB and funded by Waste Refinery, some preliminary work on textile wastes was done for checking the possibility of converting them to ethanol.

In this project optimization of the ethanol production from cotton-based materials by different pretreatment methods following enzymatic hydrolysis and fermentation was done. Furthermore, these materials after pretreatment with and without hydrolysis were digested to biogas. In addition, polyester materials was pretreated and hydrolyzed to their compounding monomers and then digested to biogas.

The aim was to develop a concept  that works for mixed materials.