The Hong Kong Research Institute of Textiles and Apparel (HKRITA) has developed a separation system to capture microplastic fibres in water by using acoustic manipulation techniques.
- Called Acousweep, the system consists of a chamber with a transducer inside that generates sweeping acoustic waves to form standing waves. The standing waves then transfer the trapped microplastic fibres to the reflector on the other side.
- When the concentration of microplastic fibres is sufficiently high, the sensory system opens a needle valve to let the microplastic fibres drip into a collection tank for further treatment.
The Project: Acousweep is a more efficient and eco-alternative to collect microplastics. The current practice uses membrane-type filters to capture such microplastics.
- Microplastic fibres can block the pores of the filters, resulting in lowering its efficiency and therefore requiring regular replacement.
- Acousweep, on the other hand, is filter-free and its processing rate is not compromised by the need to reset and replace membrane-type filters, thus achieving continuous water treatment.
- The lab scale system is able to upgrade the treatment capacity from 100 litres to 5–10 tonnes of water per hour.
- The system can be installed in a container for easy transportation and then installed in existing sewage outlets in plants.
- In addition to treating wastewater generated from the textiles and apparel industries, the Acousweep can also be applied to other industry sectors for microplastic collection.
- In the long term, the system creates a sustainable marine ecosystem through improving the quality of oceanic waters.
The Context: Microplastics, tiny plastic pieces or particles smaller than 5mm in diameter, are one of the major pollutants in oceans.
- In 2020, a report by the United Nations Environment Programme suggested that plastics make up about 60% of all clothing material.
- When washed or worn, microplastics are shed from clothes, and annually, approximately 9% of microplastics released to the ocean come from clothes and textiles.
