Integrate bubble flotation and intermittent microbubble-enhanced cold plasma activation for scalable disinfection of food processing wastewater

The food processing industry is one of the largest global consumers of potable water, generating vast volumes of pathogen-rich wastewater that pose significant treatment challenges. Cold plasma activation has emerged as a promising technology for water disinfection; however, scalability remains a critical limitation. In this study, we address this challenge by developing an integrated approach that combines flotation-based pre-treatment with intermittent microbubble-enhanced cold plasma activation (MB-CPA) for effective disinfection at varying scales. The pre-treatment step significantly reduces turbidity (∼66 %) and organic load (∼57 %) in wastewater, minimizing interference during disinfection. The novel intermittent MB-CPA technique then enables enhanced antibacterial action, achieving ∼6-log CFU/mL reduction of Gram-positive, Gram-negative, and antibiotic-resistant bacteria in both simulated and real wastewater, with a 1.3-fold increase in efficacy against E. coli compared to continuous CPA. Rapid inactivation was achieved in 10–15 min, with successful scale-up from small volumes (0.5–3.5 L, ∼ 5.7-log CFU/mL reduction) to larger volumes (10 L, ∼ 5-log CFU/mL reduction), and a strong linear relationship (R² = 0.96) between volume and exposure time highlights the scalability and feasibility of this method. This integrated system provides a transformative strategy for scalable, efficient disinfection in the meat processing industry, offering a viable solution to the critical challenge of scaling cold plasma-based water treatment for industrial applications.