Patent ID: 7595003
Filing Date: 2009-09-29
Classification: C02F

Abstract:
1. A method for treating ballast water emitted from a ballast tank of a water-borne ship, the method comprising: allowing water to flow out of the ballast tank; passing the water through a cylindrical tank after it flows out of the ballast tank, the passing comprising causing the water to enter the cylindrical tank through a water inlet and exit the cylindrical tank through a water outlet that are disposed proximate to two opposite ends of the cylindrical tank; injecting ozone into the water in the cylindrical tank via an ozone inlet disposed proximate to the water inlet; supplying acoustic energy into the water as the water passes from the water inlet to the water outlet, the acoustic energy being supplied by an acoustic mixing machine that comprises a mechanical member and an oscillator whose rotational frequency is adjusted to bring the mechanical member into resonance, the mechanical member comprising one or more of a hollow tube resonator and a solid bar that is positioned within the cylindrical tank approximately along a central axis of the cylindrical tank such that a first end of the mechanical member is proximate to the water inlet and a second end of the mechanical member is proximate to the water outlet, the mechanical member generating acoustic energy that is communicated to the ballast water contained in the cylindrical tank thereby causing the ballast water in the cylindrical tank to move through the tank from the water inlet to the water outlet with a circulating bulk flow pattern; breaking up the circulating bulk flow pattern to dissipate additional energy into the water, the breaking up occurring as the water encounters one or more acoustic focusing projections positioned within the cylindrical tank and into the circulating bulk flow pattern to thereby to dissipate additional energy into the water; and releasing the ballast water from the ship after the water exits the contactor.