RMIT University researchers enhance microplastic removal from wastewater using dual-bubble technology

RMIT University researchers have developed a new method to improve microplastic removal from wastewater, achieving removal rates exceeding 90%. This innovative dual-bubble approach, utilizing both microbubbles and nanobubbles, was detailed in a study published on July 6, 2026, in ACS ES&T Water.

Effective Microplastic Mitigation Strategy

The study, titled "Micro-Nanobubble Integrated Dissolved Air Flotation: A High-Efficiency Strategy for Microplastic Mitigation in Wastewater", highlights a significant advancement in wastewater treatment processes. Lead author, Associate Professor Biplob Pramanik, explained that this method can be easily adopted by wastewater treatment plants without the need for major infrastructure changes.

Pramanik stated, "Wastewater treatment plants are a major pathway for microplastics because they slip through filtration processes, posing risks to ecosystems and human health." The dual-bubble technique optimizes existing operating conditions such as air pressure and bubble size, enhancing the overall efficiency of microplastic removal during the primary treatment stage.

Understanding the Dual-Bubble Mechanism

The researchers discovered that the combination of microbubbles and nanobubbles significantly increases plastic removal rates compared to systems that use only one type of bubble. Microbubbles provide the necessary lifting force to bring contaminants to the surface, while nanobubbles enhance particle attachment and aggregation, leading to more effective removal.

• Microbubbles: Facilitate lifting of particles
• Nanobubbles: Improve particle interaction and aggregation
• Overall Efficiency: Achieves over 90% removal rates

Dr. Sirajum Monira, who conducted the research during her Ph.D. studies at RMIT, noted that the method performs well even under challenging wastewater conditions. She remarked, "Organic matter and fats, oils and grease did not reduce performance; in some cases, they improved it by helping microplastics clump into larger particles, making them easier to remove."

Next Steps for Implementation

With successful laboratory-scale demonstrations, the research team is eager to collaborate with industry partners to test this dual-bubble approach under real-world operating conditions. This step is crucial for validating the method across various wastewater streams, ensuring its practical applicability in combating microplastic pollution.

By effectively capturing microplastics before they accumulate in sewage sludge, this innovative approach has the potential to significantly reduce environmental contamination and protect both ecosystems and human health.