Abstract: A hydraulic conveyor for floating objects, having recirculation of a liquid composition, named conveying composition, for conveying the floating objects, includes at least one device for sanitizing the conveying composition. The sanitizing device includes: at least one device irradiating a composition, named composition to be sanitized, formed by mixing at least some of the conveying composition and an amount of a composition, named photoreactive composition, including at least one photosensitive compound that forms, under the effect of irradiation by the irradiation device, at least one compound, named active compound, transforming by chemical reaction at least one pollutant compound of the conveying composition into a non-pollutant compound; and at least two photolysis chambers mounted in series such that the composition to be sanitized can flow successively into the at least two photolysis chambers, at least one irradiation device being arranged in an inner volume of each photolysis chamber.