Treatments of plankton and Escherichia coli cells using hybrid method with water cavitation and discharge plasma

In this study, we propose a new treatment method to sanitize ballast water contaminated with plankton and/or bacteria. This method is constituted of water cavitation and discharge plasma in this cavitation field. The 0.5% brackish water containing brine shrimp (2.5 × 10⁴ and 1.25 × 10⁵ m^-3) was treated in 60 s. Then, we saw no surviving plankton in the treated water. Similarly, the treatment of water containing Escherichia coli cells (4 × 10¹⁵ m^-3) in 120 s completed the sterilization. We also observed the DNA damage and destruction of the cellular morphology after treatment. It seems that the mechanisms of sterilization are radical reactions and physical damage caused by shockwave, and radical reactions are dominant mechanism.