Study: Dual bubble method removes over 90% of microplastics from wastewater

A team of researchers in Australia has developed a method to remove more than 90 per cent of microplastics from wastewater using a combination of micro-bubbles and nano-bubbles. This method offers a practical solution to the growing global pollution problem.

According to a statement from the Royal Melbourne Institute of Technology (RMIT) Australia released on Monday (6/7), the dual-bubble approach can be adopted by wastewater treatment plants by optimising existing operational conditions, such as air pressure, saturation time, and bubble size, without requiring major changes to infrastructure.

“Wastewater treatment plants are a primary pathway for microplastics because these particles escape filtration processes, thereby posing risks to ecosystems and human health,” said the study’s lead author, Associate Professor Biplob Pramanik of RMIT.

The researchers explained that the approach enhances dissolved air flotation, a common treatment process where air bubbles attach to contaminants and lift them to the surface for removal.

Furthermore, they emphasised that the integration of micro and nano bubbles produces a much higher level of microplastic elimination compared to systems using only one type of bubble. Micro-bubbles provide the buoyancy to lift particles, while nano-bubbles increase particle adhesion and aggregation, thereby improving overall efficiency, according to the study.

The study also demonstrated that the system remains effective under realistic wastewater conditions. Organic matter and substances such as fats, oils, and grease do not hinder performance and, in some cases, actually enhance elimination by promoting the clumping of microplastics.

The research team stated that capturing microplastics during the initial treatment stage can reduce their accumulation in sewage sludge and limit their release into the environment. The team is currently seeking industrial partners to validate the approach on a large scale.