Abstract: A nanobubble-producing apparatus includes a liquid vat provided with a bubble-containing-liquid inlet in an upper part thereof and a bubble-containing-liquid outlet in a bottom part thereof, a microbubble-containing-liquid supply unit to supply microbubble-containing liquid that contains microbubbles to the bubble-containing-liquid inlet of the liquid vat, an ultrasonic collapse unit to radiate ultrasonic waves to the inside of the liquid vat so that an ultrasonic collapse field in which the collapsing of the microbubbles with the ultrasonic waves is concentrated and nanobubbles are generated is formed at a location where the microbubble-containing liquid supplied into the liquid vat through the bubble-containing-liquid inlet flows downward, and a nanobubble-containing-liquid extraction portion where the nanobubble-containing liquid that contains the nanobubbles generated by the ultrasonic collapse unit is taken out of the liquid vat through the bubble-containing-liquid outlet.

Abstract: To provide effective depuration method and depuration system for shellfish. The depuration method for shellfish comprises preparing seawater that is purified by irradiation with ultraviolet rays and made to contain oxygen gas bubbles in a storage unit, maintaining while bringing the seawater into contact with the shellfish, and deriving the seawater from the storage unit, in which the bubbles have superfine bubbles with a diameter of less than 100 nm, and the superfine bubbles selectively adsorb and desorb viruses accumulated in the shellfish. The depuration system for shellfish comprises a purification unit for purifying seawater with ultraviolet rays, a superfine bubble generating unit for generating oxygen gas bubbles with a diameter of less than 100 nm in the seawater, and a storage unit for storing the seawater, that is connected to the purification unit for purifying seawater with ultraviolet rays and the superfine bubble generating unit, in which the storage unit retains shellfish.