Could you tell us how the project was conceptualised? What was the broad objective when HKRITA started working on the concept? How long did it take for the concept to take the final shape as a machine?
The intention of the Green Machine is to develop a viable commercial solution to separate cotton and polyester blended textile. The first phase of the project started in 2016 and accomplished its lab scale development. The second phase started in 2017 which developed a pre-industrial scale system to evaluate the parameters for scaling up to the treatment conditions to industrial scale. In 2020, we worked with a textile manufacturer to set up the first industrial scale Green Machine with a processing capacity of 1.5 tonnes per day in Indonesia. Optimisation of the Green Machine continues for better operation in industrial scale. We wold be only too glad to work with interested parties to adopt the technology in its production through the approach such as technology licensing. As a matter of fact, its first licencing agreement was made with a denim manufacturer in 2021.
What was the objective laid down by the H&M Foundation when it decided to support the Green Machine project? The Foundation website says that the programme period is for 2016–24. It's 2022. So, does it mean we are likely to see more developments on Green Machine?
The Planet First programme (2020–24) is a scale up from H&M Foundation’s previous collaboration with HKRITA, named Recycling Revolution (2016–19). It aims to find planet positive technologies that will not only focus on circularity and climate change, but also consider all aspects of earth’s natural support systems. This means not only minimising or eliminating the negative impact fashion can have on the planet but adding environmental benefits to the planet through the processes and actions taken in the value chain. We’ll definitely continue working on the Green Machine, but the portfolio of projects is big—it’s changing and developing and range from using textiles that can sequester CO2 to opening up a first of its kind open lab where innovators, researchers, suppliers and brands can meet, test new ideas and scale faster. The lab will be opened in Hong Kong during 2023.
The hydrothermal method of separating fibres was developed by engineers at Shinshu University. Would you describe this as the turning point in the project?
It is a joint development between HKRITA and Shinshu University. It was an important proof-of-concept or method development stage, when HKRITA and Shinshu University engineers conduct experiments to verify the feasibility of hydrothermal method in polyester-cotton blend separation. Then, the pre-industrial sized and the industrial sized systems are further developed by our researchers according to the method.
Mechanical recycling of blended fibres is getting discarded by and by. Where does the future lie: in hydrothermal processes like this, or out-and-out chemical recycling? Related question: Is HKRITA planning to refine this Green Machine, or would you call it a complete project altogether?
The material nature of textile wastes is complicated—some are blended and some are pure. Different approaches of textile waste recycling are taken into consideration to address the issue. The Green Machine focuses on the separation of cotton and polyester blended textiles and makes the two materials reusable again after separation. Optimisation and scaling of the Green Machine continues. For example, a PET decolouring process was added in the Green Machine in the Indonesia system. It is a physical decolouring process in which dye absorbent could be re-generated again, and no chemical bleaching is involved. The treated PET fibres will become pale in colour which can extend the application of the materials.
In recycling textile waste of pure materials, there is no need to use the Green Machine.
