Integrating multiple cold plasma generators and Bernoulli-driven microbubble formation for large-volume water treatment

Cold plasma-bubble is a promising clean technology for wastewater treatment using air and electricity. However, scalability continues to pose a significant challenge to industrial applications. In this study, we integrate portable, low-power cold plasma generators with spontaneous microbubble formation in engineered venturi tubes for rapid water treatment. These tubes provide water flow channels with multiple plasma ports. The design expanded the flow rate range for stable microbubble formation from earlier reports, enabling 16 L/min and scaling up the volume of treated water to 40 L with same energy efficiency. Importantly, we identified a universal linear correlation between the total surface area of microbubbles and activation efficiency, represented by removal of a model dye, methyl orange. Significant disinfection against Gram-(−/+) bacteria with 6.68-log was confirmed in increasing water volume. Time required for effective disinfection of 4-log CFU/mL removal increases approximately linearly with volume of water, suggesting that disinfection can be achieved even at large-scale without losing the effectiveness. Increasing the plasma generator numbers (four-needle), the treatment capacity can be further improved to 120 L. Our work demonstrates that the cold plasma-bubble technology for flowing water is rapid and scalable, providing a sustainable solution for diverse industrial and environmental challenges. Synopsis: This study integrates portable, low-power cold plasma generators for microbubble enhanced activation using engineered venturi tubes, demonstrating scalable, efficient and sustainable wastewater treatment and disinfection.