Microplastics can now be separated from wastewater by using sound waves.
- The plug-and-play application — Acousweep — has been developed by the Hong Kong Research Institute of Textiles and Apparel (HKRITA) with support from the H&M Foundation.
- If the technology is implemented at an industrial scale, it will have a significant impact on the fashion industry's sustainable footprint.
The CONTEXT: Today, wastewater treatment facilities use bag filters or cartridge filters to filter microplastics from the water. Microfibres eventually block the pores of the filters resulting in lower efficiency and requiring regular replacement.
THE TECHNOLOGY: Acousweep utilises sweeping acoustic waves in a specially shaped chamber to physically trap and separate microplastic fibres from wastewater effectively.
- No chemical, solvent or biological additives are needed.
- The microplastic extraction process is a physical separation and collection as water passes through the acoustic chamber on its way to an outlet.
- The separated microplastics is drip into a collection tank for further treatment, such as recycling. The existing lab scale treatment system handles 20 litres of water per hour while the upscaled version will be able to treat 5,000–10,000 litres of water per hour.
- The technology can be easily transported and connected to any wastewater facility.
- Acousweep is designed to be retrofitted at the outlet of any wastewater treatment facility so it can ’sweep’ the water on its way out.
THE PROBLEM: A microplastic is generally defined as plastic that is less than 5mm in length (or about the size of a sesame seed and smaller). Microplastic pollution is a globally established problem and a threat to ecosystems, animals, and people.
- Microplastics come from a variety of sources, including from larger plastic debris that degrades into smaller and smaller pieces, or microbeads in exfoliating health and beauty products, or cleansers such as toothpaste.
- According to the European Environment Agency about 8% of European microplastics released to oceans are from synthetic textiles — globally, this figure is estimated at 16-35%. Between 200,000 and 500,000 tonnes of microplastics from textiles enter the global marine environment each year.
- Acousweep uses high frequency ultrasound (inaudible to humans) as an efficient way of separating the microplastics from water.
WHAT THEY SAID:
Green tech has just taken a leap forward in Hong Kong. Acousweep will help the garment and other industries to stop a highly damaging form of pollution. HKRITA used a new technique to remove the microplastics by using soundwave-based system, preventing them from getting into the sea and being ingested by sea life that can even be ingested by humans along the food chain. Acousweep has the capacity to revolutionize industry.
— Professor Christine Loh
Chief Development Strategist, Institute for the Environment
Hong Kong University of Science and Technology
As a non-profit, we have the urgent opportunity to create change by supporting disruptive research that could lead us there. Innovation is transformation and Acousweep is proof that it's worth investing in impatient research.
— Christiane Dolva
Strategy Lead
H&M Foundation
