Indonesian scientists have developed a new technology capable of filtering microplastics with underwater sound waves.

In 2022, the scientific journal Environment International published a study that confirms the omnipresence of microplastics, this time with high proportions in the bloodstream of twenty-two donors. The most common were PET polymers, mainly derived from plastic bottles. Fortunately, new scientific advances open the door for the presence of microplastics in water.

The latest strategy is configured to remove microplastics from water by using ultrasound. It's an innovative prototype developed by Indonesian researchers.

What are microplastics?

First, what exactly are microplastics? The European Commission considers plastic fragments of less than five millimetres to be microplastics. In addition to primary polymers, microplastics often contain functional additives that could pose health risks. Therefore, finding ways to reduce their presence in the environment is becoming a priority.

A prototype for removing microplastics from water

Presented at a conference of the Acoustical Society of America, the new prototype of Indonesian researchers from the Institut Teknologi Sepuluh Nopember can concentrate the microplastics present in a water stream.

Ultrasound pushes microplastics into the middle of the current in a pipe where they can leak. Preliminary technology can process up to 150 liters per hour, cleaning up to 58% of microplastics in water. Tests were conducted on three types of microplastics, with different efficiency levels recorded for each.

Of course, before applying this type of technology in natural environments, it will be necessary to assess its impact on marine fauna, especially on the creatures that depend on ecolocation, such as dolphins.

Ultrasound for cleaning sewage sludge

Using waste as a resource has become one of the main priorities in the circular economy. One of the most common alternatives is the reuse of sewage sludge to produce fertilizers.

One of the problems of this type of waste is the presence of microplastics, most of which come from washing machine cycles with synthetic garments. It is estimated that up to 8 per cent of microplastics in the oceans come from the textile industry. In turn, when sewage sludge fertilizers are used in agriculture, microplastics can contaminate the soil.

To avoid this situation, a group of scientists from the Polytechnic University of Valencia has presented a technology to remove microplastics in sewage treatment plants, also known as EDAR. Where appropriate, they have used 80 kHz ultrasound which helped to remove up to 48% of PET microplastics from mud.

This technology and that demonstrated by Indonesian scientists are still in a preliminary stage, as the use of ultrasound for cleaning microplastics dates only from the beginning of this decade.

Laser perforated microplastic filters

In addition to new ultrasound techniques, new filters are being explored that could have industrial and domestic applications. One of them has recently been introduced by the Fraunhofer Institute in Germany, which uses laser technology to create an unprecedented filter.

German researchers used an ultra-short pulse laser to puncture fifty-nine million holes just ten micrometers in diameter in a steel sheet. After testing it with water contaminated with 3D printer plastic particles, they transferred the technology to a wastewater processing plant where it is being evaluated in real conditions.

While science seeks solutions to this challenge, you can reduce your microplastic footprint by choosing natural fabrics and reusable packaging, among other measures.