The Study on the Particle Separation and Disinfection using Plasma Air Flotation System

S. Ryu, E. Hong, J. Park, S. Yoo, and T. Lho

Plasma Technology Research Center, National Fusion Research Institute, Korea

Abstract— Dissolved air flotation process (DAF) is a flotation process that can be used to remove particles in conventional type plants. But, DAF has no anti biotic ability. Plasma air flotation process (PAF), which can separate flocs by bubbles generated in underwater plasma, has developed. Plasma can generate OH radical, oxidants and micro bubbles in water. The average bubble diameter is 70 μm and it can float flocs. These bubbles and oxidants enhance degradation, separation and inactivation of organic matters and microorganisms in salt water. In this study, humic acid removal efficiency was compared between plasma air flotation process and sedimentation process based on UV254 absorbance. Separation velocity of humic acid by plasma air flotation is faster than sedimentation process. To reach 80% removal of humic acid, PAF requires 19 min and sedimentation requires 30 min and the intermittent PAF 9 min in 8 L treatment. During the 30 min PAF process 99% of disinfection of E. coli was achieved and there were no re-growth of E. coli. With these results, continuous flow reactor was developed. Flow rate of 100 ppm humic acid is 1 l/m with simultaneous 1% alum dose of 10 cc/m. The removal efficiency of humic acid is approximately 90% and 99.9% disinfection was achieved.

Keywords— Plasma, flotation, disinfection, bubbles

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