MELBOURNE, July 6 (Xinhua) -- Researchers in Australia have developed a method to remove more than 90 percent of microplastics from wastewater using a combination of microbubbles and nanobubbles, offering a practical solution to a growing global pollution problem.
The dual-bubble approach can be adopted by wastewater treatment plants by optimizing existing operating conditions such as air pressure, saturation time and bubble size, without major infrastructure changes, according to a statement from Australia's Royal Melbourne Institute of Technology (RMIT) released on Monday.
"Wastewater treatment plants are a major pathway for microplastics as they slip through filtration processes, posing risks to ecosystems and human health," said the study's lead author, RMIT Associate Professor Biplob Pramanik.
The approach enhances dissolved air flotation, a common treatment process in which air bubbles attach to contaminants and lift them to the surface for removal, researchers said, stressing significantly higher microplastic removal rates by integrating both micro- and nanobubbles, compared with systems using a single bubble type.
Microbubbles provide buoyancy to lift particles, while nanobubbles increase particle attachment and aggregation, improving overall efficiency, the study found.
The study also showed the system remained effective under realistic wastewater conditions. Organic matter and substances such as fats, oils and grease did not hinder performance and, in some cases, improved removal by promoting clumping of microplastics.
The researchers said capturing microplastics at an early treatment stage could reduce their accumulation in sewage sludge and limit environmental release. The team is seeking industry partners to validate the approach at scale. ■