Abstract
Ballast water is used to stabilize an empty ship on the open sea. It often contains various microorganisms such as plankton and bacteria, and causes serious damage to aquatic ecosystems where it is discharged. Ultra-high pressure underwater shock waves were applied to treatment those microorganisms. The imploding detonation of propane-oxygen mixture was used to generate underwater shock wave in sample holder. The authors investigated imploding detonation wave in approximately cone-shaped combustion chamber having maximum inner diameter of 60 mm. Solid particles were added in sample water to simulate real seawater. As a consequence, mortality rate was increased by the addition of large solid particles. However mortality rate was reduced with increasing concentration of small solid particles. This is considered to be due to the damping effect of underwater shock wave caused by particles.
